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3. Upon charcoal, exposed to the blowpipe flame, the three metals are volatilized, and yield a sublimate upon the charcoal. That of antimony is white, while those of bismuth and tellurium are dark yellow. By exposing them to the flame of reduction, the sublimate of tellurium disappears and communicates an intense green color to the flame. The antimony incrustation gives a feeble greenish-blue color, while the sublimate of bismuth gives no perceptible color in the light. It is, however, worthy of notice that if the operation takes place in the dark, a very pale blue flame will be seen with the bismuth.
(c.) Tin (Sn).—This metal does not occur in nature in the metallic state, very seldom in the sulphide, but chiefly in the oxide (tinstone). In the metallic state it is silver-white, possesses a very high lustre, is soft (but harder than lead), ductile, but has not much tenacity, and it is very malleable. The metal when it is cast gives a peculiar creaking noise when twisted or bent, which proceeds from the crystalline structure of the metal. This crystallization is quite clearly manifested by attacking the surface of the metal, or that of tin plate, with acids.
Tin is very slightly tarnished by exposure to the air. It fuses at 442 deg., and becomes grey, being a mixture of the oxide and the metal. At a high temperature even, tin is but little subject to pass off as vapor. It is soluble in aqua regia, and with the liberation of hydrogen, in hot sulphuric and hydrochloric acids, and in cold dilute nitric acid, without decomposing water, or the production of a gas, while nitrate of tin and nitrate of ammonia are formed. Concentrated nitric acid converts tin into insoluble tin acids.
([alpha].) Protoxide of Tin (SnO) is a dark-grey powder. Its hydrate is white, and is soluble in caustic alkalies. When this solution is heated, anhydrous crystalline black protoxide is separated. The soluble neutral salts of tin-protoxide are decomposed by the addition of water, and converted into acid soluble, and basic insoluble salts.
When protoxide of tin is ignited with free access of air, it takes fire and is converted with considerable intensity into the acids, producing white vapors. This is likewise the case if it is touched by a spark of fire from steel. The hydrate of the protoxide of tin can be ignited by the flame of a candle, and glows like tinder.
([beta].) Sesquioxide of Tin (Sn^{2}O^{3}) is a greyish-brown powder. Its hydrate is white, with a yellow tinge. It is soluble in aqua ammonia and in hydrochloric acid; this solution forms with solution of gold the "purple of Cassius."
([gamma].) Stannic Acid (peroxide, SnO^{2}).—This acid occurs in nature crystallized in quadro-octahedrons, of a brown or an intense black color, and of great hardness (tinstone). Artificially prepared, it is a white or yellowish-white powder. It exists in two distinct or isomeric modifications, one of which is insoluble in acids (natural tin-acid) while the other (tin-acid prepared in the wet way) is soluble in acids. By ignition the soluble acid is converted into the insoluble. Both modifications form hydrates.
Reactions before the Blowpipe.—Metallic tin melts easily. It is covered in the flame of oxidation into a yellowish-white oxide, which is carried off sometimes by the stream of air which propels the flame. In the reduction flame, and upon charcoal, melting tin retains its metallic lustre, while a thin sublimate is produced upon the charcoal. This sublimate is light-yellow while hot, and gives a strong light in the flame of oxidation, and turns white while cooling. This sublimate is found near to the metal, and cannot be volatilized in the oxidation flame. In the flame of reduction it is reduced to metallic tin. Sometimes this incrustation is so imperceptible that it can scarcely be distinguished from the ashes of the charcoal. If such be the case, moisten it with a solution of cobalt, and expose it to the flame of oxidation, when the sublimate will exhibit, after cooling, a bluish-green color.
Protoxide of tin takes fire in the flame of oxidation, and burns with flame and some white vapor into tin acid, or stannic acid. In a strong and continued reduction flame, it may be reduced to metal, when the same sublimate above mentioned is visible. The sesquioxide of tin behaves as the above.
Stannic acid, heated in the flame of oxidation, does not melt and is not volatilized, but produces a strong light, and appears yellowish while hot, but changing as it cools to a dirty-yellow white color. In a strong and continued flame of reduction, it may be reduced likewise to the metallic state, with the production of the same sublimate as the above.
Borax dissolves tin compounds in the flame of oxidation, and upon platinum wire, very tardily, and in small quantity, to a transparent colorless bead, which remains clear after cooling, and also when heated intermittingly. But if a saturated bead, after being completely cool, is exposed again to the flame of oxidation, at a low red heat, the bead while cooling is opaque, loses its globular form, and exhibits an indistinct crystallization. This is the case too in the flame of reduction, but if the bead is highly saturated, a part of the oxide is reduced.
Microcosmic Salt dissolves the oxides in the flame of reduction very tardily in a small quantity to a transparent colorless bead, which remains clear while cooling. If to this bead sesquioxide of iron is added in proper proportion, the sesquioxide loses its property of coloring the bead, but of course an excess of the iron salt will communicate to the bead its own characteristic color. In the flame of reduction no further alteration is visible.
Tin-oxides combine with carbonate of soda, in the flame of oxidation upon platinum wire, with intumescence to a bulky and confused mass, which is insoluble in more soda. Upon charcoal, in the reduction flame, it is easily reduced to a metallic globule. Certain compounds of tin-oxides, particularly if they contain tantalum, are by fusion with carbonate of soda reduced with difficulty; but by the addition of some borax, the reduction to the metallic state is easily effected.
Tin-oxides exposed to the oxidation flame, then moistened with a solution of cobalt, and exposed again to the flame of oxidation, will exhibit, after having completely cooled, a bluish-green color.
EIGHTH GROUP.—MERCURY, ARSENIC.
These two metals are volatilized at a temperature lower than that of a red heat, and produce, therefore, no reactions with borax and microcosmic salt. Their oxides are easily reduced to the metallic state.
(a.) Mercury (Hg).—This metal occurs in nature chiefly combined with sulphur as a bisulphide.
It occurs still more rarely in the metallic form, or combined with silver, selenium, or chlorine.
Mercury, in the metallic state, has a strong lustre, and is liquid at ordinary temperatures, whereby it is distinguished from any other metal. It freezes at 40 deg. and boils at 620 deg., but it evaporates at common temperatures. Pure mercury is unalterable. Upon being exposed to the air, it tarnishes only by admixture with other metals, turns grey on the surface, and loses its lustre. It is soluble in cold nitric acid and in concentrated hot sulphuric acid, but not in hydrochloric acid.
([chi].) Protoxide of Mercury (Hg^{2}O).—It is a black powder, which is decomposed by ignition into metallic mercury and oxygen. By digestion with certain acids, and particularly with caustic alkalies, it is converted into metallic mercury and peroxide. Some neutral salts of the protoxide are only partly soluble in water, as they are converted into basic insoluble and acid soluble salts.
Protoxide of mercury is completely insoluble in hydrochloric acid. Its neutral salts change blue litmus paper to red.
([beta].) Peroxide of Mercury (HgO).—This oxide exists in two allotropic modifications. One is of a brick-red color, and the other is orange. Being exposed to heat, they turn black, but regain their respective colors upon cooling. They are decomposed at a high temperature into metallic mercury and oxygen. They yield with acids their own peculiar salts.
Mercury, in the metallic form, can never be mistaken for any other metal in consequence of its fluid condition at ordinary temperatures.
Exposed to the blowpipe flame, it is instantly volatilized. This is also the case with it when combined with other metals. The oxides of mercury are, in the oxidation and reduction flames, instantly reduced and volatilized. They do not produce any alteration with fluxes, as they are volatilized before the bead melts. Heated with carbonate of soda in a glass tube closed at one end, they are reduced to metallic mercury, which is volatilized, and condenses upon a cool portion of the tube as a grey powder. By cautious knocking against the tube, or by rubbing with a glass rod, this sublimate can be brought together into one globule of metallic mercury. Compounds of mercury can be most completely reduced by a mixture of neutral oxalate of potassa and cyanide of potassium. If the substance under examination contains such a small quantity of mercury that it cannot be distinguished by volatilization, a strip of gold leaf may be attached to an iron wire, and introduced during the experiment in the glass tube. The smallest trace of mercury will whiten the gold leaf in spots.
(b.) Arsenic (As).—This metal occurs in considerable quantity in nature, chiefly combined with sulphur or metals.
Arsenic, in the metallic state, is of a whitish-grey color, high lustre, and is crystalline, of a foliated structure, and is so brittle that it can be pulverized. It does not melt, but is volatilized at 356 deg.. Its vapor has a strong alliaceous odor. Arsenic sublimes in irregular crystals. By exposure to the air it soon tarnishes, and is coated black. Being mixed with nitrate of potassa and inflamed, it detonates with vehemence. Mixed with carbonate of potassa, it is inflamed by a stroke of the hammer, and detonates violently.
Heated in oxygen gas, it is inflamed, and burns with a pale blue flame to arsenious acid.
([beta].) Arsenious Acid (AsO^{3}).—This acid crystallizes in octahedrons, or, when fused, forms a colorless glass, which finally becomes opaque and enamel-like, or forms a white powder. It sublimes without change or decomposition. When heated for a longer while below the temperature of sublimation, it melts into a transparent, colorless, tough glass. The opaque acid is sparingly soluble in cold water, and still more soluble in hot water. It is converted, by continued boiling, into the transparent acid, which is much more soluble in water. Arsenious acid is easily dissolved by caustic potassa. It is also soluble in hydrochloric acid. This acid occurs associated with antimonious acid, protoxide of tin, protoxide of lead, and oxide of copper. It occurs likewise in very small quantity in ferruginous mineral springs.
([gamma].)Arsenic Acid (AsO^{5}) is a white mass, which readily absorbs moisture and dissolves. It will not volatilize at a low red heat, nor will it decompose. Exposed to a strong heat, it is decomposed, yielding oxygen, and passing into arsenious acid.
Reactions before the Blowpipe.
Metallic arsenic, heated in a glass tube closed at one end, yields a black sublimate of a metallic lustre, and at the same time gives out the characteristic alliaceous odor. This is the case too with alloys of arsenic, if there is a maximum quantity of arsenic present.
When heated in a glass tube open at both ends, metallic arsenic is oxidized to arsenious acid, which appears as a white crystalline sublimate on the sides of the glass tube. This deposit will occur at some distance from the assay, in consequence of the great volatility of the arsenic. The sublimate can be driven from one place upon the tube to another, by a very low heat. Alloys of arsenic are converted into basic arseniates of metal oxides, while surplus arsenic is converted into arsenious acid, which sublimes on the tube. If too much arsenic is used for this experiment, a dark-brown incrustation will sublime upon the sides of the tube which will give an alliaceous smell. If this sublimate should be deposited near the assay, then it resembles the white sublimate of arsenious acid.
Heated upon charcoal, metallic arsenic is volatilized before it melts, and incrusts the charcoal in the flame of oxidation as a white deposit of arsenious acid. This sublimate appears sometimes of a greyish color, and takes place at some distance from the assay. When heated slightly with the blowpipe flame, this sublimate is instantly driven away, and being heated rapidly in the reduction flame, it disappears with a light blue tinge, while the usual alliaceous or garlic smell may be discerned.
Arsenious acid sublimes in both glass tubes very readily, as a white crystalline sublimate. These crystals appear to be regular octahedrons when observed under the microscope. Upon charcoal it instantly volatilizes, and when heated, the characteristic garlic smell may be observed.
Arsenic acid yields, heated strongly in a glass tube closed at one end, oxygen and arsenious acid, the latter of which sublimes in the cool portions of the tube. Compounds of arsenic produce, in consequence of their volatility, no reactions with fluxes. Being heated upon charcoal with carbonate of soda, they are reduced to metallic arsenic which may be detected by the alliaceous odor peculiar to all the arsenic compounds when volatilized.
NINTH GROUP.—COPPER, SILVER, GOLD.
These metals are not volatile, neither are their oxides. They are reduced to the metallic state, by fusion with carbonate of soda, when they melt to a metallic grain. The oxides of silver and gold are reduced per se to the metallic state by ignition. In the reduction of the oxides of this group, no sublimate is visible upon the charcoal.
(a.) Copper (Cu).—This metal occurs in the metallic state, also as the protoxide, and as oxides combined with acids in different salts (carbonate of copper as malachite, etc.) The sulphide of copper is the principal ore of copper occurring in nature. In the metallic state, copper is of a red color, has great lustre and tenacity, is ductile and malleable, and crystallizes in octahedrons and cubes. It melts at a bright red heat, is more difficult than silver to fuse, but fuses more readily than gold. It absorbs oxygen while melting. There arises from its surface a fine dust of metallic globules, which are covered with the protoxide. The surface of the metal is likewise covered with the protoxide. Copper exposed to moist air tarnishes, and is converted into hydratic carbonate of copper. When ignited in the open air, it is soon covered with the brownish-red protoxide.
([chi].) Protoxide of Copper (Cu^{2}O).—This oxide occurs in nature, crystallized in octahedrons of a ruby-red color, of a lamellar structure, and transparent. Artificially prepared, it forms a powder of the same color. It is decomposed by dilute acids into salts of peroxide and metal. It is converted by ignition, with free access of air, into peroxide.
([beta].) Oxide of Copper (CuO).—This oxide is a dark-brown or black powder. It is dissolved by acids, with a blue or green-colored solution. It is soluble in aqua ammonia, and the solution is of a dark blue color.
Reactions before the Blowpipe.—Oxide of copper exposed upon platinum wire to the inmost flame (the blue flame), communicates to the external flame a green color. Heated upon charcoal in the oxidation flame, it melts to a black ball, soon spreads over the charcoal, and is partially reduced.
Exposed to the reduction flame, at a temperature which will not melt copper, it is reduced with a bright metallic lustre, but as soon as the blast ceases, the surface of the metal becomes oxidized, and appears dark brown or black. If the temperature is continued still higher, it melts to a metallic grain.
Borax dissolves the oxide of copper in the flame of oxidation to a clear green-colored bead, even if the quantity of oxide be quite small, but by cooling, the bead becomes blue. In the flame of reduction upon platinum wire, the bead soon becomes colorless, but while cooling presents a red color (protoxide of copper). This bead is opaque, but, if too much of the oxide is added, a part of it is reduced to metal, which is visible by breaking the metallic grain.
Upon charcoal, the oxide is reduced to the metal, and the bead appears colorless after cooling. With the addition of some tin, the bead becomes brownish-red and opaque after cooling.
Microcosmic Salt dissolves oxide of copper in the flame of oxidation to a green bead, not so intensely colored as the borax bead. In the reduction flame the bead, if pretty well saturated, becomes dark-green while hot, and brownish-red when cool, opaque and enamel-like. If the oxide is so little that no reaction is visible, by the addition of some tin, the bead appears colorless while hot, and dark brownish-red and opaque when cold.
Carbonate of Soda dissolves oxide of copper in the oxidation flame upon platinum wire, to a clear, green bead, which loses its color when cooling, and becomes opaque.
Upon charcoal, it is reduced to the metal, the soda is absorbed by the charcoal, and the metallic particles melt with sufficient heat to a grain.
(b.) Silver (Ag).—This metal occurs in nature in the metallic state, and in combination with other metals, particularly with lead. It also occurs as the sulphide in several mines. It crystallizes in cubes and octahedrons; is of a pure white color, great lustre, is very malleable and ductile, and is softer than copper, but harder than gold. It is not oxidizable, neither at common temperatures nor at those which are considerably higher. It is soluble in dilute nitric acid, and in boiling concentrated sulphuric acid.
([chi].) Protoxide of Silver (Ag^{2}O).—It is a black powder. It is converted by acids and ammonia into oxide and metal.
([beta].) Oxide of Silver (AgO).—It is a greyish-brown or black powder, and is the base of the silver salts. With aqua ammonia, it is converted into the black, fulminating silver.
([gamma].) Superoxide or Binoxide of Silver (AgO^{2}).—This oxide occurs in black needles or octahedral crystals of great metallic lustre. It is dissolved by the oxygen acids with the disengagement of oxygen gas.
Behavior before the Blowpipe.—When exposed to the flames of oxidation and reduction, the oxides of silver are instantly reduced to the metallic state.
Borax dissolves silver-oxides upon platinum wire in the oxidation flame but partially, while the other portion is reduced, the bead appearing opalescent after cooling, in correspondence to the degree of saturation. The bead becomes grey in the flame of reduction, the reduced silver melting to a grain, and the bead is rendered clear and colorless again.
Microcosmic Salt dissolves oxides of silver in the flame of oxidation upon platinum wire to a transparent yellowish bead, which presents, when much of the oxide is present, an opalescent appearance.
In the flame of reduction, the reaction is analogous to that of borax.
By fusion with carbonate of soda in the oxidation and reduction flames, the silver oxides are instantly reduced to metallic silver, which fuses into one or more grains.
(c.) Gold (Au).—This metal occurs mostly in the metallic state, but frequently mixed with ores, and with other metals. Gold crystallizes in cubes and octahedrons, is of a beautiful yellow color, great lustre, and is the most malleable and ductile of all the metals. It melts at a higher temperature than copper, gives a green colored light when fused, and contracts greatly when cooling. It does not oxidize at ordinary temperatures, nor when heated much above them. It is soluble in nitro-hydrochloric acid (aqua regia).
([chi].) Protoxide of Gold (Au^{2}O).—This oxide is a dark violet colored powder which is converted by a temperature of 540 deg. into metallic gold and oxygen. It is only soluble in aqua regia. Treated with hydrochloric acid, it yields the chloride of gold and the metal. With aqua ammonia, it yields the fulminating gold, which is a blue mass and very explosive.
([chi].) Peroxide of Gold (Au^{2}O^{3}).—This oxide is an olive-green or dark brown powder, containing variable quantities of water. Decomposed at 530 deg., it yields metallic gold and oxygen.
Reactions before the Blowpipe.—Oxides of gold are reduced, in both the oxidation and reduction flames, to the metal, which fuses to grains.
Borax does not dissolve it, but it is reduced to the metallic state in this flux in either flame. The reduced metal fuses upon charcoal to a grain.
Microcosmic Salt presents the same reactions as borax.
When fused with soda, upon charcoal, the soda is absorbed, and the gold remains as a metallic grain.
TENTH GROUP.—MOLYBDENUM, OSMIUM.
These metals are not volatile, and are infusible before the blowpipe; but some of their oxides are volatile, and can be reduced to an infusible metallic powder.
(a.) Molybdenum (Mo) occurs in the metallic state; also combined with sulphur, or as molybdic acid combined with lead. It is a white, brittle metal, and is unaltered by exposure to the air. When heated until it begins to glow, it is converted into a brown oxide. Heated at a continued dull red heat, it turns blue. At a higher temperature, it is oxidized to molybdic acid, when it glimmers and smokes, and is converted into crystallized molybdic acid upon the surface.
([chi].) Protoxide of Molybdenum (MoO).—This oxide is a black powder.
([chi].) Deutoxide of Molybdenum (MoO^{2}).—This oxide is a dark copper-colored crystalline powder.
Reactions before the Blowpipe.—Metallic molybdenum, its protoxide and binoxide, are converted in the oxidation flame into molybdic acid. This acid fuses in the flame of oxidation to a brown liquid, which spreads, volatilizes, and sublimes upon the charcoal as a yellow powder, which appears crystalline in the vicinity of the assay. This sublimate becomes white after cooling. Beyond this sublimate there is visible a thin and not volatile ore of binoxide, after cooling; this is of a dark copper-red color, and presenting a metallic lustre.
Heated in a glass tube, closed at one end, it melts to a brown mass, vaporizes and sublimates to a white powder upon a cool portion of the tube. Immediately above the assay, yellow crystals are visible; these crystals are colorless after cooling, and the fused mass becomes light yellow-colored and crystalline.
Upon platinum foil, in the flame of oxidation, it melts and vaporizes, and becomes light yellow and crystalline after cooling. In the reduction flame it becomes blue, and brown-colored if the heat is increased.
Upon charcoal, in the reduction flame, it is absorbed by the charcoal; and, with an increase of the temperature, it is reduced to the metal, which remains as a grey powder after washing off the particles of charcoal.
Borax dissolves it, in the oxidation flame, upon platinum wire easily, and in great quantity, to a clear yellow, which becomes colorless while cooling. By the addition of more of the molybdenic acid the bead is dark yellow, or red while hot, and opalescent when cold. In the reduction flame, the color of the bead is changed to brown and transparent. By the addition of more of the acid, it becomes opaque.
Microcosmic Salt dissolves it in the oxidation flame, upon platinum wire, to a clear, yellowish-green bead, which becomes colorless after cooling. In the reduction flame the bead is very dark and opaque, but becomes of a bright green after cooling. This is the case likewise upon charcoal.
Carbonate of Soda dissolves it upon platinum wire in the oxidation flame with intumescence, to a clear bead, which appears milk-white after cooling. Upon charcoal the soda and the molybdic acid are absorbed, the latter is reduced to the metallic state, the metal remaining as a grey powder after washing off the particles of charcoal. When molybdic acid, or any other oxide of this metal, is exposed upon platinum wire, or with platinum tongs, to the point of the blue flame, a yellowish-green color is communicated to the external flame. If also any of the compounds of molybdenum are mixed in the form of a powder with concentrated sulphuric acid and alcohol, and the latter inflamed, the flame of the alcohol appears colored green.
(c.) Osmium (Os).—This metal occurs associated with platinum. It is of a bluish-grey color, and is very brittle. Ignited in the open air, it is oxidized to volatile osmic acid, which is possessed of a pungent smell, and affects the eyes. It communicates a bright white color to the flame of alcohol. Osmium oxide (OsO^{2}) is converted in the oxidation flame to osmic acid, which is volatilized with a peculiar smell, leaving a sublimate.
In the reduction flame it is reduced to a dark-brown infusible metallic powder. It produces no reactions with fluxes. Carbonate of soda reduces it upon charcoal to an infusible metallic powder, which appears, after washing off the particles of charcoal, of a dark-brown color.
ELEVENTH GROUP.—PLATINUM, PALLADIUM, IRIDIUM, RHODIUM, RUTHENIUM.
These metals are infusible before the blowpipe. They are not volatile, nor are they oxidizable. Their oxides are, in both flames, reduced to a metallic and infusible powder. They give no reactions with fluxes, but are separated in the metallic form. These metals are generally found associated together in the native platinum, also with traces of copper, lead, and iron.
The metal palladium is found native, associated with iridium and platinum. This metal generally occurs in greatest quantity in Brazil.
The metal rhodium is found along with platinum, but in very small quantities.
Iridium occurs in nature associated with osmium, gold, and platinum, in the mines of Russia. Its great hardness has rendered it desirable for the points of gold pens. In South America this metal is found native, associated with platinum and osmium. The latter metal, associated with platinum and iridium, has been found in South America.
As these metals will not oxidize or dissolve, they cannot be separated from each other by the blowpipe with the reagents peculiar to that species of analysis. It is true that colors may be discerned in the beads, but these tints proceed from the presence of small traces of copper, iron, etc.
The ore of osmium and iridium can be decomposed, and the former recognized by its fetid odor. This metal, strongly ignited in a glass tube with nitrate of potash, is converted to the oxide of osmium, which gives an odor not unlike the chloride of sulphur.
As the metals of this group are very rare ones, especially the last four ones, we shall not devote an especial division to each of them. For a more detailed statement of their reactions, the student is referred to the large works upon blowpipe analysis.
CLASS III.
NON-METALLIC SUBSTANCES.
1. Water—2. Nitric Acid—3. Carbon—4. Phosphorus —5. Sulphur—6. Boron—7. Silicon—8. Chlorine —9. Bromine—10. Iodine—11. Fluorine—12. Cyanogen —13. Selenium.
(1.) Water (HO).—Pure distilled water is composed of one volume of oxygen, and two volumes of hydrogen gases; or, by weight, of one part of hydrogen to eight parts of oxygen gases. Water is never found pure in nature, but possessing great solvent properties, it always is found with variable proportions of those substances it is most liable to meet with, dissolved in it. Thus it derives various designations depending upon the nature of the substance it may hold in solution, as lime-water, etc.
In taking cognizance of water in relation to blowpipe analysis, we regard it only as existing in minerals. The examination for water is generally performed thus: the substance may be placed in a dry tube, and then submitted to heat over a spirit-lamp. If the water exists in the mineral mechanically it will soon be driven off, but if it exists chemically combined, the heat will fail to drive it off, or if it does, it will only partially effect it. The water will condense upon the cool portions of the tube, where it can be readily discerned. If the water exists chemically combined, a much stronger heat must be applied in order to separate it.
Many substances may be perhaps mistaken for water by the beginner, such as the volatile acids, etc.
(2.) Nitric Acid (NO^{5}).—Nitric acid occurs in nature in potash and soda saltpetre. These salts are generally impure, containing lime, as the sulphate, carbonate and nitrate, and also iron in small quantity. The soda saltpetre generally contains a quantity of the chloride of sodium. The salts containing nitric acid deflagrate when heated on charcoal. Substances containing nitric acid may be heated in a glass tube closed at one end, by which the characteristic red fumes of nitrous acid are eliminated. If the acid be in too minute a quantity to be thus distinguished, a portion of the substance may be intimately mixed with some bisulphate of potash, and treated as above. The sulphuric acid of the bisulphate combines with the base, and liberates the nitric acid, while the tube contains the nitrous acid gas.
The nitrate of potassa, when heated in a glass tube, fuses to a clear glass, but gives off no water. When fused on platinum wire, it communicates to the external flame the characteristic violet color. When fused and ignited on charcoal, its surface becomes frothy, indicating the nitric acid.
(3.) Carbon (C).—Carbon is found in nature in the pure crystallized state as the diamond. It occurs likewise in several allotropic states as graphite, plumbago, charcoal, anthracite, etc. It exists in large quantities combined with oxygen as carbonic acid.
The diamond, although combustible, requires too high a heat for its combustion to enable us to burn it with the blowpipe. When excluded from the air, it may be heated to whiteness without undergoing fusion, but with the free access of air it burns at a temperature of 703 deg. C, and is converted into carbonic acid. If mixed with nitre, the potassa retains the carbonic acid, and the carbon may be thus easily estimated. If a mineral containing carbonic acid is heated, the gas escapes with effervescence, or a strong mineral acid as the hydrochloric will expel the acid with the characteristic effervescence.
(4.) Phosphorus, Phosphoric Acid (PO^{6}).—This acid occurs in a variety of minerals, associated with yttria, copper, uranium, iron, lead, manganese, etc. Phosphoric acid may be detected in minerals by pursuing the following process: dip a small piece of the mineral in sulphuric acid, and place it in the platinum tongs: this is heated at the point of the blue flame, when the outer flame will become colored of a greenish-blue hue. This color will not be mistaken for those of boracic acid, copper, or baryta. Some of the phosphoric minerals, when heated in the inner flame, will color the outer flame green.
If alumina be present with the phosphoric acid, the following wet method should be adopted for the detection of the latter: the substance should be powdered in the agate mortar with a mixture of six parts of soda, and one and a half parts of silica. The entire mass should now be placed on charcoal, and melted in the flame of oxidation. The residue should be treated with boiling water, which dissolves the phosphate and the excess of carbonate of soda, while the silicate of alumina, with some of the soda, is left. The clear liquor is now treated with acetic acid, and heated over the spirit-lamp, and a small portion of crystallized nitrate of silver added; a lemon-yellow precipitate of phosphate of silver is quickly developed. Previous to the addition of the nitrate, the liquor should be well heated; otherwise, a white precipitate of dipyrophosphate of silver will be produced.
If the examination be of any of the metallic phosphides, the substances should be powdered in the agate mortar, and fused with nitrate of potassa on the platinum wire; the fused mass should be treated with soda in the same manner as any substance containing phosphoric acid. The metal and the phosphorus are oxidized, while the phosphate of potassa is fused, and the metallic oxide separates.
(5.) Sulphur (S).—Sulphur is found native in crystals It is frequently found associated with lime, iron, silica, carbon, etc., and combined extensively with metals.
The principal acid of sulphur (the sulphuric, SO^{3}) occurs combined with the earths, the alkalies, and the metallic oxides. Native sulphur is recognized, when heated upon charcoal, by its odor (sulphurous acid) and the blue color of its flame. The compounds of sulphur may be detected by several methods. If the substance is heated in a glass tube, closed at one end, the yellow sublimate of sulphur will subside upon the cool portions of the tube; if the substance should also contain arsenic, the sublimate will present itself as a light brown incrustation, consisting of the sulphide of arsenic.
If the assay is heated in the open glass tube, sulphurous acid will thus be generated; but, if the gas is too little to be detected by the smell, a strip of moistened litmus paper will indicate the presence of the acid.
The assay will give off sulphurous fumes if heated in the flame of oxidation.
If the powdered substance is fused with two parts of soda, and one part of borax, upon charcoal, the sulphide of sodium is formed. This salt, if moistened and applied to a polished silver surface, will blacken it. The borax serves no other purpose than to prevent the absorption of the formed sulphide of sodium by the charcoal. As selenium will blacken silver in the manner above indicated, the presence of this substance should be first ascertained, by heating the assay; when, if it be present, the characteristic horse-radish odor will reveal the fact.
Sulphuric acid may be detected by fusing the substance with two parts of soda, and one part of borax, on charcoal, in the flame of reduction; the mass must now be wetted with water, and placed in contact with a surface of bright silver; when, if sulphuric acid be present, the silver will become blackened.
Or the substance may be fused with silicate of soda in the flame of reduction. In this case, the soda combines with a portion of the sulphuric acid, which is then reduced to the sulphide, while the bead becomes of an orange or red color, depending upon the amount of the sulphuric acid present. If the assay should, however, be colored, then the previous treatment should be resorted to.
(6.) Boron, Boracic Acid (BO^{3}).—This acid occurs in nature in several minerals combined with various bases, such as magnesia, lime, soda, alumina, etc. Combined with water, this acid exists in nature as the native boracic acid; this acid gives with test paper prepared from Brazil wood, when moistened with water, a characteristic reaction, for the paper becomes completely bleached. An alcohol solution turns curcuma test paper brown. Heated on charcoal, it fuses to a clear bead; but, if the sulphate of lime be present, the bead becomes opaque upon cooling.
The following reaction is a certain one: the substance is pulverized and mixed with a flux of four and a half parts of bisulphate of potassa, and one part of pulverized fluoride of calcium. The whole is made into a paste with water, and the assay is placed on the platinum wire, and submitted to the point of the blue flame. While the assay is melting, fluoboric gas is disengaged, which tinges the outer flame green. If but a small portion of boracic acid is present, the color will be quite evanescent.
(7.) Silica, Silicic Acid (SiO^{3}).—This acid exists in the greatest plenty, forming no inconsiderable portion of the solid part of this earth. It exists nearly pure in crystallized quartz, chalcedony, cornelian, flint, etc., the coloring ingredients of these minerals being generally iron or manganese.
With microcosmic salt, silica forms a bead in the flame of oxidation which, while hot, is clear, while the separated silica floats in it. A platinum wire is generally used for the purpose, the end of it being first dipped in the salt which is fused into a bead, after which the silica must be added, and then the bead submitted to the flame of oxidation.
The silicates dissolve in soda but partially, and then with effervescence. If the oxygen of the acid be twice that of the base, a clear bead will be obtained that will retain its transparency when cold. If the soda be added in small quantity, the bead will then be opaque. In the first instance, a part of the base which separates is re-dissolved, and, therefore, the transparency of the glass; but, if too large a quantity of the soda is added, the separation of the base is sufficient to render the assay infusible.
(8.) Chlorine (Cl).—Chlorine exists in nature always in combination, as the chlorides of sodium, potassium, calcium, ammonium, magnesia, silver, mercury, lead, copper, etc.
The chlorine existing in metallic chlorides may be detected as follows: the wet way may be accomplished in the following manner. If the substance is insoluble, it must be melted with soda to render it soluble; if it be already soluble it must be dissolved in pure water, and nitrate of silver added, when the one ten-thousandth part of chlorine will manifest its presence by imparting a milky hue to the fluid.
By the blowpipe, chlorine may be detected in the following manner: Oxide of copper is dissolved in microcosmic salt on the platinum wire in the flame of oxidation, and a clear bead is obtained. The substance containing the chlorine is now added, and heat is applied. The assay will soon be enveloped by a blue or purplish flame. As none of the acids that occur in the mineral kingdom give this reaction, chlorine cannot be confounded with them, for those which impart a color to the flame, when mixed with a copper salt, will not do so when tested in the microcosmic salt bead as above indicated.
If the assay is soluble in water, the following method may be followed: a small quantity of sulphate of copper or iron is dissolved; a few drops of the solution is placed upon a bright surface of silver, and the metallic chloride added; when, if chlorine is present, the silver is blackened. If the chloride is insoluble in water, it must be rendered soluble by fusion upon a platinum wire with soda, and then treated as above.[2]
[2] Plattner.
(9.) Bromine (Br).—The bromide of magnesium and sodium exists in many salt springs, and it is from these that the bromine of commerce is obtained. The metallic bromides give the same reactions on silver with the microcosmic bead and copper salt as the metallic chlorides. The purplish color which, however, characterizes the chlorides, is more inclined to greenish with the bromides. If the substance be placed in a flask or glass tube, and fused with bisulphate of potassa, over the spirit-lamp, sulphurous gas and bromine will be eliminated. Bromine will be readily detected by its yellow color and its smell. Bromine may be readily detected by passing a current of chlorine through the fluid, after which ether is added and the whole is agitated. The ether rises to the top, carrying with it the bromine in solution; after being withdrawn, this ether is mixed with potassa, by which the bromide and bromate of potassa are formed. The solution is evaporated to dryness, the residue is fused in a platinum vessel, the bromate is decomposed, while the bromide remains; this must be distilled with sulphuric acid and the binoxide of manganese. A red or brown vapor will then appear, indicating the presence of bromine; this vapor will color starch paste—which may be put in the receiver on purpose—of a deep orange color.
If, to a solution containing a bromide, concentrated sulphuric or nitric acid be added, the bromine is liberated and colors the solution yellow or red. The hypochlorites act in the same manner. The bromine salts are coming into use extensively in photography, in consequence of their greater sensitiveness to the action of light than the chlorides alone.
(10.) Iodine (I).—This element occurs in salt-springs, generally combined with sodium; it also exists in rock-salt; it has likewise been found in sea-water, also in a mineral from Mexico, in combination with silver, and in one from Silesia, in combination with zinc. As sea-water contains iodine, we would consequently expect to find it existing in the sea-weeds, and it is generally from the ashes of these that it is obtained in commerce.
When the metallic iodides are fused with the microcosmic salt and copper, as previously indicated, they impart a green color to the flame. This color cannot be mistaken for the color imparted to the flame by copper alone. When the metallic iodides are fused in a glass tube, closed at one end, with the bisulphate of potassa, the vapor of iodine is liberated, and may be recognized by its characteristic color. Those mineral waters containing iodine can be treated the same as for bromine, as previously indicated, while the violet-colored vapor of the iodine can be easily discerned. The nitrate of silver is the best test for iodine, the yellow color of the iodide of silver being not easily mistaken, while its almost insolubility in ammonia will confirm its identity. The chloride of silver, on the contrary, dissolves in ammonia with the greatest facility.
The reactions of iodine are similar to those of bromine with concentrated sulphuric acid and binoxide of manganese, and with nitric acid: The iodine is released and, if the quantity be not too great, colors the liquid brown. If there be a considerable quantity of iodine present, it is precipitated as a dark colored powder. Either of these, when heated, gives out the violet-color of the iodine.
With starch paste free iodine combines, producing a deep blue compound. If, however, the iodine be in very minute quantity, the color, instead of being blue, will be light violet or rose color.
If to a solution of the sulphate of copper, to which a small portion of sulphurous acid has been added, a liquid containing iodine and bromine is poured in, a dirty, white precipitate of the subiodide of copper is produced, and the bromine remains in the solution. The latter may then be tested for the bromine by strong sulphuric acid.
(11.) Fluorine (Fl).—This element exists combined with sodium, calcium, lithium, aluminium, magnesium, yttrium, and cerium. Fluorine also exists in the enamel of the teeth, and in the bones of some animals. This element has a strong affinity for hydrogen, and, therefore, we find it frequently in the form of hydrofluoric acid. Brazil-wood paper is the most delicate test for hydrofluoric acid, which it tinges of a light yellow color. Phosphoric acid likewise colors Brazil paper yellow, but as this acid is not volatile at a heat sufficient to examine hydrofluoric acid, there can be no mistake. If the substance is supposed to contain this acid, it should be placed on a slip of glass, and moistened with hydrochloric acid, when the test paper may be applied, and the characteristic yellow color will indicate the presence of the fluorine.
As hydrofluoric acid acts upon glass, this property may be used for its detection. The substance may be put into a glass tube, and sulphuric acid poured upon it in sufficient quantity to moisten it; a slight heat applied to the tube will develop the acid, which will act upon the glass of the tube. If the acid is retained in the mineral by a feeble affinity, and water be present, a piece of it may be put in the tube and heated, when the acid gas will be eliminated. The test paper will indicate its presence, even before it has time to act upon the glass. If the temperature be too high, fluosilicic acid is generated, and will form a silicious incrustation upon the cool portion of the tube.
If the fluorine is too minute to produce either of the above reactions, then the following process, recommended by Plattner, should be followed: the assay should be mixed with metaphosphate of soda, formed by heating the microcosmic salt to dull redness. The mass must then be placed in an open glass tube, in such a position that there will be an access of hot air from the flame. Thus aqueous hydrofluoric acid is formed, which can be recognized by its smell being more suffocating than chlorine, and also by the etching produced by the condensation of vapor in the tube. Moist Brazil paper, applied to the extremity of the tube, will be instantly colored yellow.
Merlet's method for the detection of this acid is the following:[3] Pulverize the substance for examination, then triturate it to an impalpable powder, and mix it with an equal part of bisulphate of potassa. Heat the mass gradually in a moderately wide test-tube. The judicious application of heat must be strictly observed, for if the operator first heats the part of the tube where the assay rests, the whole may be lost on account of the glass being shattered. The spirit-flame must be first applied to the fore part of the tube, and then made to recede slowly until it fuses the assay. After the mixture has been for some time kept in a molten state, the lamp must be withdrawn, and the part containing the assay severed with a file. The fore part of the tube must then be well washed, and afterwards dried with bibulous paper. Should the fluorine contained in the substance be appreciable, the glass tube, when held up to the light, will be found to have lost its transparency, and to be very rough to the touch.
[3] Quoted by Plattner.
Great care should be observed not to allow this very corrosive acid to come into contact with the skin, as an ulcer will be the consequence that will be extremely difficult to heal.
When hydrofluoric acid comes in contact with any silicious substance, hydrofluosilicic acid gas is always formed.
(12.) Selenium (Se).—This element occurs in combination with lead as the selenide, and with copper as the selenide of copper. It exists also combined with cobalt and lead, as the selenide of these metals; also as the selenide of lead and mercury.
The smallest trace of selenium may be detected by igniting a small piece of charcoal in the flame of oxidation, when the peculiar and unmistakable odor of decayed horse-radish will indicate the presence of that element. An orange vapor is eliminated if the selenium be present in any quantity, while there is an incrustation around the assay of a grey color, with a metallic lustre. This incrustation frequently presents a reddish-violet color at its exterior edges, often running into a deep blue. If a substance containing selenium be placed in a glass tube, closed at one end, and submitted to heat, the selenium is sublimed, with an orange-colored vapor, and with the characteristic odor of that substance. Upon the cool portions of the tube a steel-grey sublimate is deposited, and, beyond that, can be discerned small crystals of selenic acid. If the mineral be the seleniferous lead glance, sulphurous acid gas will be given off, and may be detected by the smell, or by a strip of moistened litmus paper.
If arsenic is present, heating upon charcoal will quickly lead to the determination of the one from the other.
* * * * *
TABULAR STATEMENT OF THE REACTIONS OF MINERALS BEFORE THE BLOWPIPE.
In PART THIRD of this work, commencing at page 109, the student will find a sufficiently explicit description of the blowpipe reactions of those principal substances that would be likely to come beneath his attention. The following tabular statement of those reactions—which we take from Scheerer and Blanford's excellent little work upon the blowpipe—will be of great benefit, as a vehicle for consultation, when the want of time—or during the hurry of an examination—precludes the attentive perusal of the more lengthy descriptions in the text.
In the examination of minerals, before the student avails himself of the aid of the blowpipe, he should not neglect to examine the specimen rigidly in relation to its physical characters, such as its hardness, lustre, color, and peculiar crystallization. It is where the difference of two minerals cannot be distinguished by their physical appearance, that the aid of the blowpipe comes in most significantly as an auxiliary. For instance, the two minerals molybdenite and graphite resemble each other very closely, when examined in regard to their physical appearance, but the blowpipe will quickly discriminate them, for if a small piece of the former mineral be placed in the flame of oxidation, a bright green color will be communicated to the flame beyond it, while in the latter there will be no color. Thus, in a very short time, these two minerals can be distinguished from each other by aid of the blowpipe, while no amount of physical examination could determine that point. The blowpipe is equally an indispensable instrument in the determination of certain minerals which may exist in others as essential or non-essential constituents of them. For instance, should a minute quantity of manganese be present in a mineral, it must be fused with twice its bulk of a mixture of two parts of carbonate of soda, and one part of the nitrate of potassa, in the flame of oxidation upon platinum foil. The manganate of soda thus formed will color the fused mass of a bluish-green tint.
Or a slight quantity of arsenic may be discerned by the following process recommended by Plattner:[4] one grain of the finely pulverized metal is mixed with six grains of citrate of potassa, and slowly heated on the platinum spoon. By this means the metals are oxidized, while the arseniate of potassa is obtained. Then boil the fused mass in a small quantity of water in a porcelain vessel till all tho arseniate is dissolved. The metallic oxides are allowed to subside, and the above solution decanted off into another porcelain vessel. A few drops of sulphuric acid are added, and the solution boiled to expel the nitric acid, after which it is evaporated to dryness. In this operation, the sulphuric acid should be added only in sufficient quantity to drive off the nitric acid, or, at the utmost, to form a bisulphate with the excess of potassa. When dry, the salt thus obtained is pulverized in an agate mortar, and mixed with about three times its volume of oxalate of potassa, and a little charcoal powder. The mixture is introduced into a glass bulb having a narrow neck, and gently warmed over a spirit-lamp in order to drive off the moisture, which must be absorbed by a piece of blotting-paper in the neck of the bulb. After a short time, the temperature is increased to a low red heat, at which the arsenious acid is reduced and the metallic arsenic sublimed, and which re-condenses in the neck of the bulb. If there the arsenic be so small in quantity as to exhibit no metallic lustre, the neck of the bulb may be cut off with a file immediately above the sublimate, and the latter exposed to the flame of the blowpipe, when the arsenic is volatilized, and may be recognized by its garlic odor.
[4] Quoted by Scheerer.
If the presence of cadmium is suspected in zinc-blende, it may be detected by fusing a small piece of the blende upon charcoal in carbonate of soda. The peculiar bright yellow sublimate of the oxide of cadmium, if it be present, will not fail to indicate it. This incrustation can be easily distinguished from that of zinc. Thus, with the three illustrations we have given, the student will readily comprehend the great utility of the blowpipe in the examination of minerals.
Although the following tables were not arranged especially for the last part of this work, still this arrangement is so good that by their consultation the student will readily comprehend at a glance what requires some detail to explain, and we feel no hesitation in saying that, although they are not very copious, they will not fail to impart a vast amount of information, if consulted with any degree of carefulness.
The minerals given are such as are best known to English and American mineralogists under the names specified. For more detailed reactions than could be crowded into a table, the student will have to consult the particular substance as treated in Part Third. If this part is perused carefully previous to consulting the tables, these will be found eminently serviceable as a refresher of the memory, and may thus save much time and trouble.
And, finally, we would certainly recommend the student, after he shall have gone through our little volume (if he is ambitious of making himself a thorough blowpipe analyst), to then take up the larger works of Berzelius and Plattner, for our treatise pretends to nothing more than a humble introduction to these more copious and scientific works.
* * * * *
Mineral. Diamond
Formula. C
Behavior
in glass-bulb. —
on platinum foil. In fine powder is slowly consumed without residue in a strong oxidizing Flame.
* * * * *
Mineral. Graphite
Formula. C with some iron silica, etc.
Behavior
in glass-bulb. Generally gives off water.
on platinum foil. Is slowly consumed leaving more or less ash, principally Fe^{2}O^{3}.
* * * * *
Mineral. Anthracite
Formula. C + xḢ
Behavior
in glass-bulb. Evolves water.
on platinum foil. Is slowly consumed with the exception of a small quantity of ash.
* * * * *
Mineral. Wallsend-coal
Formula. C, H, O, S and ash.
Behavior
in glass-bulb. Intumesces and gives off water and tarry matters which partly condense in bulb, and leave a porous coke.
on platinum foil. Takes fire under blowpipe flame, and burns with a smoky flame, depositing much soot and leaving a porous cinder which burns slowly and leaves a small ash.
* * * * *
Mineral. Cannel-coal
Formula. C, H, N, O, S and ash.
Behavior
in glass-bulb. As the preceding but gives off more tar.
on platinum foil. Similar to the preceding. If held to the lamp-flame, takes fire and burns for some seconds.
* * * * *
Mineral. Brown-coal
Formula. C, H, N, O, S, and ash.
Behavior
in glass-bulb. Gives off much water and tar, and leaves a porous cinder retaining the form of the original fragment.
on platinum foil. Burns slowly and without flame, leaving some ash.
* * * * *
Mineral. Asphaltum
Formula. C + H + O.
Behavior
in glass-bulb. Fuses with ease affording an empyreumatic oil having an alkaline reaction, and combustible gasses, and leaves a carbonaceous residue, which is entirely consumed under the blowpipe flame, except a little ash.
on platinum foil. Takes fire and burns with a bright flame and a thick smoke.
* * * * *
Mineral. Elaterite
Formula. C + H.
Behavior
in glass-bulb. Fuses and gives off water having an acid reaction, naphtha and a tarry fluid, which chiefly condense in the neck of the bulb, and leave a light, pulverulent carbonaceous residue.
on platinum foil. Fuses, takes fire, and burns with a smoky flame, leaving a carbonaceous residue, which under the blowpipe flame, is quickly consumed, with the exception of the ashes.
* * * * *
Mineral. Hachettine
Formula. C + H.
Behavior
in glass-bulb. Fuses to a clear colorless liquid, which solidifies on cooling and has a tallow-like smell.
on platinum foil. Fuses, takes fire, and burns with a bright flame until entirely consumed.
* * * * *
Mineral. Ozokerite
Formula. C + H.
Behavior
in glass-bulb. Fuses readily to a clear brown oily fluid, which solidifies on cooling.
on platinum foil. As the preceding.
* * * * *
Mineral. Amber
Formula. C + H + O.
Behavior
in glass-bulb. Fuses with difficulty, and affords water, an empyreumatic oil, and succinic acid which condense in the neck of the bulb leaving a shining black residue.
on platinum foil. Takes fire and burns with a yellow flame and a peculiar aromatic odor.
* * * * *
Mineral. Mellite
Formula. [...Al]M^{3} + 15Ḣ
Behavior
in glass-bulb. Gives off water. If heated to redness, is carbonized, and gives a slight empyreumatic odor.
on platinum foil. On charcoal burns to a white ash, which moistened with nitrate of cobalt and heated shows the alumina reaction.
* * * * *
POTASH.
* * * * *
Mineral. Nitre
Formula. K[.....N]
Behavior
(1) in glass-bulb. Fuses readily to a clear liquid and with a strong heat boils with the evolution of oxygen.
(2) in open tube. —
(3) on charcoal. Deflagrates leaving a saline mass, which is absorbed into charcoal and gives a sulphur reaction on silver.
(4) in forceps. On platinum wire fuses and colors the flame violet more or less modified by lime and soda.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. —
(8) Special reactions. With bisulphate of potassa in the glass-bulb evolves nitrous fumes.
* * * * *
Mineral. Polyhalite
Formula. K[...S]+[.Mg][...S]+2[.Ca][...S]+2Ḣ
Behavior
(1) in glass-bulb. Gives off water.
(2) in open tube. —
(3) on charcoal. Fuses to a reddish bead, which in the reducing flame solidifies and shrinks to a hollow crust.
(4) in forceps. On platinum wire fuses and colors the flame yellow from a small quantity of soda.
(5) in borax. Dissolves with ebullition to a clear glass, which is slightly colored by iron, and when saturated become opaque on cooling.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses. The alkalies are absorbed by the charcoal leaving the lime and magnesia infusible on the surface.
(8) Special reactions. The alkaline mass when laid on silver gives a sulphur reaction.
* * * * *
SODA.
* * * * *
Mineral. Rock-salt
Formula. NaCl.
Behavior
(1) in glass-bulb. Fuses to a clear liquid
(2) in open tube. —
(3) on charcoal. Fuses, is absorbed by the charcoal and partially volatilized incrusting the charcoal around.
(4) in forceps. Fuses with great ease and colors the flame yellow.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. —
(8) Special reactions. Gives the chlorine reactions.
* * * * *
Mineral. Natron
Formula. [.Na][..C] + 10Ḣ
Behavior
(1) in glass-bulb. Fuses, with the evolution of water.
(2) in open tube. —
(3) on charcoal. Fuses, and is absorbed into the pores of the charcoal.
(4) in forceps. Fuses and behaves as the preceding.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. —
(8) Special reactions. Dissolves in acid with violent effervescence.
* * * * *
Mineral. Soda-nitre
Formula. [.Na][.....N].
Behavior
(1) in glass-bulb. Fuses and if strongly heated evolves nitrous fumes. (2) in open tube. — (3) on charcoal. Deflagrates and is absorbed into the charcoal.
(4) in forceps. Deflagrates on platinum wire, coloring the flame yellow.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. —
(8) Special reactions. In a glass-bulb with bisulphate of potassa, gives the NO^{5}-reaction.
* * * * *
Mineral. Glauber-salt
Formula. [.Na][...S] + 10Ḣ.
Behavior
(1) in glass-bulb. Fuses and gives off water having a neutral reaction.
(2) in open tube. —
(3) on charcoal. Fuses, and is absorbed by the charcoal. The saturated charcoal laid upon silver gives the sulphur reaction
(4) in forceps. Fuses and colors the flame yellow.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. —
(8) Special reactions. Gives the SO^{3}-reaction.
* * * * *
Mineral. Glauberite
Formula. [.Na][...S] + [.Ca][...S].
Behavior
(1) in glass-bulb. Decrepitates with the evolution of more or less water, and when strongly heated fuses to a clear liquid.
(2) in open tube. —
(3) on charcoal. Fuses to a clear bead, then spreads out; the soda is absorbed and the lime left on the surface. Laid on silver, the fused mass gives a sulphur reaction.
(4) in forceps. Fuses easily to a clear glass, coloring the flame yellow.
(5) in borax. Fuses easily and gives the lime reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. As alone in charcoal.
(8) Special reactions. As in preceding.
* * * * *
Mineral. Borax
Formula. [.Na][...B]^{2}+10Ḣ.
Behavior
(1) in glass-bulb. Intumesces with the evolution of water, and under a strong heat fuses.
(2) in open tube. —
(3) on charcoal. Intumesces and fuses to a clear bead more or less colored by impurities.
(4) in forceps. As on charcoal.
(5) in borax. —
(6) in mic. salt. —
(7) with carb. soda. Fuses to a clear bead, which becomes crystalline on cooling.
(8) Special reactions. Gives the boracic-acid-reaction.
* * * * *
Mineral. Cryolite
Formula. 3NaFl+Al^{2}Fl^{3}.
Behavior
(1) in glass-bulb. Decrepitates slightly and gives a trace of water.
(2) in open tube. If heated so that the flame be allowed to play up the tube upon the mineral, flourine is evolved, which corrodes the interior of the tube.
(3) on charcoal. Fuses to a limpid bead, which on cooling becomes a white enamel. If heated for some time, it bubbles, gives off fluorine and becomes infusible.
(4) in forceps. Fuses, coloring the flame yellow.
(5) in borax. Dissolves to a clear bead, which is rendered opaque by a large addition.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a clear bead, then spreads out on the charcoal, the soda is absorbed, and an infusible mass of alumina remains.
(8) Special reactions. If the alumina residue obtained be moistened with cobalt solution and heated strongly, it assumes a beautiful blue color.
* * * * *
BARYTA AND STRONTIA.
* * * * *
Mineral. Heavy-spar
Formula. [.Ba][...S].
Behavior
(1) in glass-bulb. Sometimes decrepitates and gives off more or less water
(2) in open tube. —
(3) on charcoal. Fuses in the reducing flame.
(4) in forceps. Fuses with difficulty on edges. Colors the outer flame green. In reducing flame forms BaS, which fuses readily.
(5) in borax. Gives the baryta-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a clear bead; then spreads out and is absorbed into the charcoal. The fused mass laid on silver gives the S-reaction.
(8) Special reactions. If fused with potassa on platinum, gives the SO^{3}-reaction.
* * * * *
Mineral. Celestine
Formula. [.Sr][...S].
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. Fuses to a milk-white bead.
(4) in forceps. Colors the flame crimson.
(5) in borax. Gives the strontia-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Similar to the preceding.
(8) Special reactions. Similar to the preceding.
* * * * *
Mineral. Witherite
Formula. [.Ba][..C].
Behavior
(1) in glass-bulb. Decrepitates more or less and evolves Water.
(2) in open tube. —
(3) on charcoal. Fuses, effervesces, and is partially absorbed by the charcoal.
(4) in forceps. Colors the outer flame intensely green.
(5) in borax. Dissolves with effervescence and gives the baryta-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a clear bead; then spreads out and passes into the charcoal.
(8) Special reactions. In dilute HCl dissolves with much effervescence.
* * * * *
Mineral. Strontianite
Formula. [.Sr][..C].
Behavior
(1) in glass-bulb. Becomes opaque.
(2) in open tube. —
(3) on charcoal. As in the forceps.
(4) in forceps. Exfoliates and becomes arborescent. The filaments glow brilliantly and fuse on the point. Colors the flame brilliantly crimson.
(5) in borax. Resembles the preceding.
(6) in mic. salt. As in borax.
(7) with carb. soda. As the preceding.
(8) Special reactions. As the preceding.
* * * * *
Mineral. Barytocalcite.
Formula. [.Ba][..C] + [.Ca][..C].
Behavior
(1) in glass-bulb. As in the preceding.
(2) in open tube. —
(3) on charcoal. In powder frits together, but does not fuse.
(4) in forceps. Colors the flame green in the centre and red towards the point.
(5) in borax. Dissolves with effervescence. In large quantities gives a semi-crystalline bead.
(6) in mic. salt. As in borax, but the saturated bead is milk-white.
(7) with carb. soda. Fuses, and is partially absorbed leaving the lime on the surface.
(8) Special reactions. As witherite.
* * * * *
LIME.
* * * * *
Mineral. Gypsum
Formula. [.Ca][...S] + 2Ḣ.
Behavior
(1) in glass-bulb. Turns white, giving off water and being converted into plaster of Paris.
(2) in open tube. —
(3) on charcoal. In the reducing flame forms CaS, which has an alkaline reaction on test paper, and gives a sulphur-reaction when laid on silver and moistened.
(4) in forceps. Fuses with difficulty to a bead, coloring the flame red.
(5) in borax. Dissolves to a clear bead, which gives the lime- reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Behaves as lime. The alkaline mass laid on silver and moistened gives the sulphur-reaction.
(8) Special reactions. Gives the sulphuric-acid reaction.
* * * * *
Mineral. Apatite { Cl Formula. [.Ca]{ — +3[.Ca]^{3}[.....P] { Fl Behavior
(1) in glass-bulb. Occasionally decrepitates and gives off some water.
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. IV. Previously dipped in SO^{3} colors the flame green, afterwards red.
(5) in borax. Dissolves easily and when in some quantity gives an opaline bead.
(6) in mic. salt. Gives the lime-reaction.
(7) with carb. soda. Is infusible. The alkali is absorbed, leaving the lime on the on the surface of the charcoal.
(8) Special reactions. With microcosmic salt and oxide of copper, gives the chlorine-reaction. With microcosmic salt in the open tube evolves fluorine.
* * * * *
Mineral. Pharmacolite
Formula. [.Ca]^{2}[.....As] + 6Ḣ.
Behavior
(1) in glass-bulb. Gives off water, and emits an arsenical odor.
(2) in open tube. —
(3) on charcoal. Fuses to an opaque bead and emits a strong smell of arsenic.
(4) in forceps. Fuses to a translucent violet colored bead, the color being due to cobalt. Colors the flame blue at first, then faintly red.
(5) in borax. Dissolves readily to a bead strongly colored by cobalt, which obscures the lime-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses, and emits As. The alkali is then absorbed by the charcoal, as in the preceding.
(8) Special reactions. —
* * * * *
Mineral. Calespar
Formula. [.Ca][..C].
Behavior
(1) in glass-bulb. Turns white and sometimes decrepitates. Strongly heated loses CO^{2} and becomes caustic.
(2) in open tube. —
(3) on charcoal. Turns white, or brown if containing much iron or manganese and glows brilliantly.
(4) in forceps. Glows brilliantly, coloring the flame red. Becomes caustic and shows a strong alkaline reaction.
(5) in borax. Dissolves with evolution of CO^{2} and when pure gives the lime-reaction. The bead is generally more or less colored by iron and manganese.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses, and behaves as other lime-salts.
(8) Special reactions. Dissolves with effervescence in cold HCl.
* * * * *
Mineral. Fluorspar
Formula. CaFl
Behavior
(1) in glass-bulb. Phosphoresces with various colors, when heated in the dark.
(2) in open tube. —
(3) on charcoal. Fuses easily to a clear bead, which becomes opaque on cooling, then loses fluorine, glows brilliantly and becomes infusible.
(4) in forceps. As on charcoal. Colors the flame red.
(5) in borax. Gives the lime-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a clear bead, opaque on cooling. With an addition of the alkali behaves as lime.
(8) Special reactions. With microcosmic salt in open tube gives the fluorine-reaction.
* * * * *
MAGNESIA.
* * * * *
Mineral. Brucite
Formula. [.Mg]Ḣ.
Behavior
(1) in glass-bulb. Evolves water.
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V.
(5) in borax. Behaves as magnesia. Sometimes gives a faint iron-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Behaves as magnesia.
(8) Special reactions. With nitrate of cobalt, gives the magnesia reaction
* * * * *
Mineral. Epsomite
Formula. [.Mg][...S] + 7Ḣ.
Behavior
(1) in glass-bulb. Evolves water having an acid reaction on test paper.
(2) in open tube. —
(3) on charcoal. Gives of HO and SO^{3}, shines brilliantly, and becomes alkaline and caustic.
(4) in forceps. V. As on charcoal.
(5) in borax. Behaves as magnesia.
(6) in mic. salt. As in borax.
(7) with carb. soda. The alkali is absorbed leaving the magnesia on surface of the charcoal. Gives the sulphur-reaction on silver.
(8) Special reactions. The magnesian residue obtained on treating with carbonate of soda (7), assumes a flesh-tint, when treated with cobalt.
* * * * *
Mineral. Boracite
Formula. [.Mg][...B]^{2} + 2[.Mg][...B].
Behavior
(1) in glass-bulb. Occasionally gives off a trace of water.
(2) in open tube. —
(3) on charcoal. Fuses with intumescence to a white crystalline bead.
(4) in forceps. I. As on charcoal. Colors the flame green.
(5) in borax. Fuses easily to a clear bead, which is crystalline, when containing much of the mineral, and is usually slightly tinted by iron.
(6) in mic. salt. As in borax.
(7) with carb. soda. With a small quantity of alkali fuses to a clear bead on cooling. With a larger quantity gives a clear, uncrystallizable bead.
(8) Special reactions. —
* * * * *
Mineral. Magnesite
Formula. [.Mg][..C].
Behavior
(1) in glass-bulb. Sometimes gives off a small quantity of water.
(2) in open tube. —
(3) on charcoal. Is infusible. With cobalt-solution, assumes a dusky flesh tint.
(4) in forceps. —
(5) in borax. Behaves as magnesia. Sometimes a slight iron-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a bead, the soda is then absorbed, leaving an infusable mass of magnesia.
(8) Special reactions. The magnesian residue obtained by fusing with carbonate of soda gives the magnesian-reaction with nitrate of cobalt. Dissolves with effervescence in warm HCl.
* * * * *
Mineral. Mesitine spar
Formula. ([.Mg][.Fe][.Mn])[..C].
Behavior
(1) in glass-bulb. As magnesite.
(2) in open tube. —
(3) on charcoal. Is infusible. Assumes a deep brown color.
(4) in forceps. V.
(5) in borax. Gives the iron and manganese-reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. As magnesite, but the residual mass has a dark color from iron and manganese.
(8) Special reactions. Dissolves with effervescense in warm HCl. With carbonate of soda and nitre gives a manganese-reaction.
* * * * *
ALUMINA.
* * * * *
Mineral. Sapphire Corundum Emery
Formula. [...Al=].
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V.
(5) in borax. In fine powder dissolves slowly to a colorless glass.
(6) in mic. salt. As in borax.
(7) with carb. soda. —
(8) Special reactions. In fine powder moistened with cobalt-solution and heated yields a blue color.
* * * * *
Mineral. Websterite
Formula. [...Al][...S] + 9Ḣ.
Behavior
(1) in glass-bulb. Gives off water, and, when heated to incipient redness, sulphurous acid.
(2) in open tube. —
(3) on charcoal. Gives off water and SO^{3}, leaving an infusible mass.
(4) in forceps. V.
(5) in borax. Behaves as alumina.
(6) in mic. salt. As in borax.
(7) with carb. soda. Yields an infusible mass, which laid on silver and moistened, produces a black stain.
(8) Special reactions. Fused with potassa in platinum has no action on silver. Cobalt-solution produces the alumina reaction.
* * * * *
Mineral. Native Alum
Formula. Ṙ[...S] + [...Al][...S]^{3} + 24Ḣ.
Behavior
(1) in glass-bulb. Intumesces greatly and gives off much water. Strongly heated, evolves SO^{3}, which reddens litmus.
(2) in open tube. —
(3) on charcoal. Intumesces and become infusible.
(4) in forceps. V. Colors the flame violet if a potassa alum—yellow if soda—be present.
(5) in borax. Dissolves and gives the iron and manganese reaction, if these oxides be present. Otherwise the bead is colorless.
(6) in mic. salt. As in borax.
(7) with carb. soda. The alkali is absorbed into the charcoal, leaving an infusable mass which gives the sulfur reaction on silver.
(8) Special reactions. If not containing too much iron or manganese gives an alumina reaction with nitrate of of cobalt. In other respects as the preceding.
* * * * *
Mineral. Turquoise
Formula. [...Al=]^{2}[.....P] + 5Ḣ.
Behavior
(1) in glass-bulb. Evolves water, occasionally decrepitates and turns black.
(2) in open tube. —
(3) on charcoal. Turns brown, but remains infusible.
(4) in forceps. V. As on charcoal. Colors the outer flame green.
(5) in borax. In the oxidizing flame, gives a green bead, due to copper and iron. In reducing flame, opaque red.
(6) in mic. salt. As in borax.
(7) with carb. soda. Intumesces, then fuses to a semi-clear glass colored by iron. With more alkali yields an infusible mass.
(8) Special reactions. Gives the phosphoric-acid reaction.
* * * * *
Mineral. Wavellite
Formula. [Al=]F^{3} + 3([...Al=]^{4}[.....P]^{3} + 18Ḣ.)
Behavior
(1) in glass-bulb. Evolves water and some fluorine, which attacks the glass.
(2) in open tube. —
(3) on charcoal. Exfoliates and turns white.
(4) in forceps. V. As on charcoal. Colors the outer flame green, especially if moistened with SO^{3}.
(5) in borax. As alumina. Generally gives also a slight iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Forms an infusible white mass.
(8) Special reactions. With cobalt-solution on charcoal gives the alumina reaction.
* * * * *
Mineral. Spinel
Formula. Ṙ[...Al=].
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V.
(5) in borax. Gives a slight iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses partially and forms a porous mass.
(8) Special reactions. With nitrate of cobalt gives the alumina reaction. With nitre and carbonate of soda a slight manganese reaction.
* * * * *
SILICATES.
The presence of silica in a mineral can easily be ascertained by treating a small fragment in a bead of microcosmic salt. The bases will dissolve out with more or less difficulty in the salt, and the silica being insoluble will remain suspended in the bead, retaining the original form of the fragment. In borax, the silicates of lime and magnesia generally dissolve with considerable ease, but those of alumina slowly and with difficulty. The silicates of lime are moreover frequently characterized by intumescence or ebullition, when heated in the forceps in the blowpipe flame. The minerals presenting this character are marked in the table. As the most convenient mode of classifying the silicates for blowpipe examination, the following arrangement will be adopted:
TABLE I.—ANHYDROUS SILICATES.
TABLE II.—HYDROUS SILICATES.
FUSIBILITY.
I. Readily fusible to a bead. II. With difficulty fusible to a bead. III. Readily fusible on the edges. IV. With difficulty fusible on the edges. V. Infusible.
a. Afford a fluid bead with carbonate of soda. b. Afford a fluid bead with but little of that salt, but with a larger quantity a slaggy mass. c. Afford a slaggy mass only.
This classification of minerals, according to their fusibility and their behavior with carbonate of soda, was originally proposed by Berzelius, and a table of the principal oxidized minerals arranged according to these characters is given in his handbook of the blowpipe, and thence adopted, with some alterations by Plattner, in the very excellent and detailed work already many times cited. In the following general table I., the more important silicates only are included, and in table II. are enumerated in alphabetical order those which afford characteristic reactions.
TABLE I.
Anhydrous Silicates. Fus. alone and with NaC.
Mineral. Formula. I. a. Axinite ([.Ca][.Mg])^{3}([...B][...Si])^{3} + ([...Al=][...Fe=][...Mn=])^{2}([...Si][...B]) Int. Elaolite (K[.Na])^{3}[...Si] + 3[...Al=][...Si] Int. Garnet Ṙ^{3}[...Si] + [.R][...Si] Oligoclase [.Na][...Si] + [...Al][...Si]^{2} Scapolite ([.Ca][.Na])^{3}[...Si]^{2} + 2[...Al=][...Si] Int. Spodumene ([.Li][.Na])^{3}[...Si]^{2} + 4[...Al=][...Si]^{2}Int. b. Asbestos As Hornblende to II. Augite ([.Ca][.Mg][.Fe][.Mn])^{3}[...Si]^{2} Int. some var. Epidote ([.Ca]Fe)^{3}[...Si] + Int. to III. 2([...Al][...Fe][...Mn])[...Si] Hornblende ([.Ca][.Mg][.Fe])^{4} + ([...Si][...Al=])^{3} Int. some var. Sodalite [.Na]^{3}[...Si] + 3[...Al=][...Si] + NaCl Int. to III. Vesuvian 3([.Ca][.Mg])^{3}[...Si] + 2([...Al=][...Fe=])[...Si] Int. c. Biaxial Mica K[...Si] + 4([...Al=][...Fe=])[...Si] to III. Hauyne (K[.Na])^{3}[...Si] + 3[...Al=][...Si] + [.Na][...Si] Tourmaline (Ṙ[...R=][...B])^{4}[...Si]^{3} Int. to V.
II. a. Labradorite ([.Ca][.Na]K)[...Si] + ([...Al=][...Fe=])[...Si] Lepidolite (KNaL)F + ([...Al=][...Fe=])[...Si]^{2}? Ryacolite K[...Si] + [...Al=][...Si]^{2} Albite [.Na][...Si] + [...Al=][...Si]^{3} b. Augite Ṙ^{3}[...Si]^{2} some var. Actinolite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3} Int. Diopside ([.Ca][.Mg])^{3}[...Si]^{2} Humboltilite 2([.Ca][.Mg][.Na]K)[...Si] + ([...Al=][...Fe=])[...Si] Sahlite As Augite Tremolite ([.Ca][.Mg])^{4}[...Si]^{3} c. Pyrope ([.Ca][.Mg][.Fe])^{3}[...Si] + Al[...Si] + m[...Cr]?
III. a. Anorthite ([.Ca][.Mg][.Na]K)^{3}[...Si] + 3([...Al=][...Fe=])[...Si] Nepheline ([.Na]K[.Ca])^{2}[...Si] + 2[...Al=][...Si] Obsidian [...Si],[...Al=],[...Fe=],[.Fe],[.Ca][.Na]K Int. Orthoclase (K[.Na])[...Si] + [...Al=][...Si]^{3} Petalite ([.Li][.Na])^{3}[...Si]^{4} + 4[...Al=][...Si]^{4} Pumice [...Si],[...Al=],[.Ca],K,[.Na],Ḣ Int. b. Gadolinite (Ẏ[.Ce][.La][.Fe][.Ca])^{3}[...Si] to V. Nephrite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3}? Int. Wollastonite [.Ca]^{3}[...Si]^{2} c. Iolite ([.Mg][.Fe])^{3}[...Si]^{2} + 3[...Al=][...Si]
IV. a. Beryl [...Be][...Si]^{2} + [...Al=][...Si]^{2} b. Diallage ([.Ca][.Mg][.Fe])^{3}([...Si][...Al=])^{2} Hypersthene ([.Mg][.Fe])^{3}[...Si]^{2} c. Fuchsite (K^{5}[...Si])^{2} + 9([...Al=][...Cr=])^{6}[...Si]^{6} V. a. Leucite K^{3}[...Si]^{2} + [...Al=][...Si]^{2} b. Chondrodite ([.Mg],[.Mg]F)^{4}([...Si]SiF^{3}) Olivine ([.Mg][.Fe][.Ca])^{2}[...Si] c. Andalusite ([...Al=]Fe)^{3}[...Si]^{2} Chrysoberyl [...Be] + [...Al=] Kaynite [...Al=]^{3}[...Si]^{2} Pycnite 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + 2[...Si]F^{3}) Topaz 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + 2[...Si]F^{3}) Zircon [...Zr=][...Si] Staurolite ([...Al=]Fe)^{2}[...Si]
Hydrous Silicates. Fus. alone and with NaC.
Mineral. Formula. I. a. Analcime [.Na]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + 6Ḣ Int. Apophyllite (K, KF)([...Si], SiF^{3}) + 6[.Ca][...Si] + 15Ḣ Int. Brewsterite ([.Sr][.Ba])[...Si] + [...Al=][...Si]^{3} + 5Ḣ Int. Chabasite ([.Ca],[.Na],K)^{3}[...Si] + 3[...Al=][...Si]^{2} + 18Ḣ Int. Lapis Lazuli [...Si],[...S],[...Al=], Fe, [.Ca], [.Na], Ḣ Laumonite [.Ca]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + 12Ḣ Int. Mesotype ([.Na][.Ca])[...Si] + [...Al=][...Si] + 3Ḣ Int. Natrolite [.Na][...Si] + [...Al=][...Si] + 2Ḣ Int. Prehnite [.Ca]^{2}[...Si] + [...Al=][...Si] + Ḣ Int. Scolezite [.Ca][...Si] + [...Al=][...Si] + 3Ḣ Int. Thomsonite ([.Ca][.Na])^{3}[...Si] + 3[...Al=][...Si] + 7Ḣ Int. Datholite 2[.Ca]^{3}[...Si] + [...B]^{3}[...Si]^{2} + 3Ḣ Int. Heulandite [.Ca][...Si] + [...Al=][...Si]^{3} + 5Ḣ Int. Stilbite [.Ca][...Si] + [...Al=][...Si]^{3} + 6Ḣ Int. b. Okenite [.Ca]^{3}[...Si]^{4} + 6Ḣ Int. Pectolite ([.Ca][.Na])^{4}[...Si]^{3} + Ḣ Int. c. Saponite 2[.Mg]^{3}[...Si]^{2} + [...Al=][...Si] + 10 or 6Ḣ II. a. Antrimolite 3([.Ca]K)[...Si] + 5[...Al=][...Si] + 15Ḣ Harmatome [...Ba][...Si] + [...Al=]S^{2} + 5Ḣ b. Brevicite [.Na][...Si] + [...Al=][...Si] + 2Ḣ Orthite Ṙ^{3}[...Si] + [...R=][...Si] + (Ḣ?) Int.
III. c. Pitchstone [...Si],[...Al=], Fe, [.Mg][.Na], KḢ Talc to V. [.Mg]^{6}[...Si]^{5} + 2Ḣ Chlorite 3([.Mg]Fe)^{3}[...Si] + ([...Al=]Fe)^{2}[...Si] + 9Ḣ Pinite [...Si],[...Al=],[.Fe],K,[.Mg],Ḣ
IV. a. Steatite [.Mg]^{6}[...Si]^{5} + 4Ḣ c. Gilbertite [...Si],[...Al=],[.Fe],[.Mg],Ḣ Int. Meerschaum [.Mg][...Si] + Ḣ Serpentine [.Mg]^{9}[...Si]^{4} + 6Ḣ V. a. Gismondine ([.Ca]K)^{2}[...Si] + 2[...Al=][...Si] + 9Ḣ
TABLE II.
Analcime If transparent becomes white and opaque when heated, but on incipient fusion resumes its transparency and then fuses to a clear glass. Andalusite When powdered and treated with cobalt solution on charcoal, assumes a blue color. Apophyllite Fuses to a frothy white glass. Axinite Imparts a green color to the blowpipe flame, owing to the presence of boracic acid. This reaction is especially distinct, if the mineral be previously mixed with fluorspar and bisulphate of potassa. Beryl Sometimes gives a chromium reaction in borax and microcosmic salt. Chabasite Fuses to a white enamel. Chondrodite Evolves fluorine in the glass tube, both when heated alone and with microcosmic salt. It sometimes also gives off a trace of water. Chrysoberyl Is unattacked by carbonate of soda. With nitrate of cobalt on charcoal the finely powdered mineral assumes a blue color. Datholite Fuses to a clear glass and colors the flame green. Diallage Frequently gives off water in small quantity. Fuchsite Gives the chromium reaction with borax and microcosmic salt. Gadolinite That from Hitteroe, if heated in a partially covered platinum spoon to low redness, glows suddenly and brilliantly. Hauyne Affords the sulphur reaction both on charcoal and when fused with potassa. It contains both sulphur and sulphuric acid. Hypersthene As Diallage. Kyanite As Andalusite. Lapis Lazuli Fuses to a white glass, and when treated with carbonate of soda on charcoal, gives the sulphur reaction on silver. Laumonite When strongly heated, exfoliates and curls up. Lepidolite Colors the blowpipe flame crimson, from lithia; also gives the fluorine reaction with microcosmic salt. Leucite Some varieties, when treated with cobalt solution, assume a blue color. Meerschaum In the glass bulb frequently blackens and evolves an empyreumatic odor due to organic matter. When this is burnt off, it again becomes white, and if moistened with nitrate of cobalt solution and heated, assumes a pink color. Okenite Behaves as Apophyllite. Olivine Some varieties give off fluorine, when fused with microcosmic salt. Pectolite Similar to Apophyllite. Petalite Imparts a slight crimson color to the flame, like Lepidolite. Prehnite As Chabasite. Pycnite Assumes a blue color, when treated with nitrate of cobalt. Gives the fluorine reaction with microcosmic salt. Pyrope Gives the chromium reaction with borax and microcosmic salt. Scolecite Similar to Laumonite, but more marked. Scapolite Occasionally contains a small quantity of lithia, and colors the flame red when fused with fluorspar and bisulphate of potassa. Sodalite If mixed with one-fifth its volume of oxide of copper, moistened to make the mixture cohere, and a small portion placed upon charcoal and heated with the blue oxidizing flame, the outer flame will be colored intensely blue from chloride of copper. Spodumene When not too strongly heated, colors the blowpipe flame red, when more strongly, yellow. Stilbite As Chabasite. Topaz When heated, remains clear. Otherwise as Pycnite. Tourmaline Gives the boracic acid reaction with flourspar and bisulphate of potassa. Wollastonite Colors the blowpipe flame faintly red from lime. Zircon The colored varieties become white or colorless and transparent, when heated. Is only slightly attacked by carbonate of soda.
* * * * *
URANIUM.
* * * * *
Mineral. Pitchblende
Formula. U[...U=] essentially.
Behavior
(1) in glass-bulb. Evolves some water and a small quantity of sulphur, sulphide of arsenic and metallic arsenic.
(2) in open tube. Evolves SO^{2} and a white sublimate of arsenious acid.
(3) on charcoal. Gives off arsenical fumes.
(4) in forceps. III. Colors the flame blue beyond the assay, owing to the presence of Pb. Sometimes also green towards the point, due to Cu.
(5) in borax. The roasted mineral affords the uranium reaction.
(6) in mic. salt. As borax. Also a small residue of silica.
(7) with carb. soda. Infusible. Affords the characteristic Pb incrustation, and sometimes yields minute particles of Cu.
(8) Special reactions. —
* * * * *
Mineral. Uranium ochre
Formula. [...U=]Ḣ^{2}. Behavior
(1) in glass-bulb. Evolves water and assumes a red color.
(2) in open tube. —
(3) on charcoal. V. In reducing flame assumes a green color.
(4) in forceps. —
(5) in borax. Gives the uranium reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. —
(8) Special reactions. —
* * * * *
Mineral. Uranite
Formula. ([.Ca] +[...U=]^{2})[.....]P + 8Ḣ.
Behavior
(1) in glass-bulb. Evolves water and becomes yellow and opaque.
(2) in open tube. —
(3) on charcoal. Fuses with intumescence to a black bead having a semi-crystalline surface.
(4) in forceps. —
(5) in borax. Gives the uranium reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Forms an infusible yellow slag.
(8) Special reactions. Gives the PO^{5} reaction.
* * * * *
Mineral. Chalcolite
Formula. ([.Cu]+[...U=]^{2})[.....P] + 8Ḣ.
Behavior
(1) in glass-bulb. As uranite.
(2) in open tube. —
(3) on charcoal. As uranite.
(4) in forceps. As uranite.
(5) in borax. In the oxidizing flame gives a green bead, which in the reducing flame becomes of an opaque red, from Cu.
(6) in mic. salt. As in borax.
(7) with carb. soda. In reducing flame yields a metallic bead of Cu.
(8) Special reactions. As uranite.
* * * * *
IRON.
* * * * *
Mineral. Iron pyrites
Formula. FeS^{2}.
Behavior
(1) in glass-bulb. Gives a considerable yellow sublimate of sulphur, and sometimes sulphide of arsenic. Also HS.
(2) in open tube. Sulphurous acid and sometimes arsenious acid are evolved.
(3) on charcoal. Gives off some sulphur, which burns with a blue flame. Residue fuses to a magnetic bead.
(4) in forceps. —
(5) in borax. The roasted mineral gives a strong iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Fuses to a black mass, which spreads out on charcoal and gives the sulphur reaction on silver.
(8) Special reactions. —
* * * * *
Mineral. Magnetic pyrites
Formula. [,Fe]^{5}[,,,Fe=]. Behavior
(1) in glass-bulb. —
(2) in open tube. Evolves sulphurous acid.
(3) on charcoal. Fuses to a magnetic bead black on the surface, and with a yellow shining fracture.
(4) in forceps. —
(5) in borax. As iron pyrites.
(6) in mic. salt. As in borax.
(7) with carb. soda. As iron pyrites.
(8) Special reactions. —
* * * * *
Mineral. Mispickel
Formula. FeAs + FeS^{2}.
Behavior
(1) in glass-bulb. A red sublimate of AsS^{2} is first formed and then a black sublimate of metallic arsenic.
(2) in open tube. Sulphurous and arsenious acids are evolved, the latter forming a white sublimate.
(3) on charcoal. Gives off much arsenic forming a white incrustation and fuses to a magnetic globule.
(4) in forceps. —
(5) in borax. As iron pyrites.
(6) in mic. salt. As in borax.
(7) with carb. soda. As iron pyrites.
(8) Special reactions. —
* * * * *
Mineral. Magnetic iron ore
Formula. Fe^{3}O^{4}
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. In the blue flame, fuses on edges and remains magnetic.
(5) in borax. Gives the iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. —
(8) Special reactions. —
* * * * *
Mineral. Specular iron Red haematite
Formula. Fe^{2}O^{3}
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V. In the blue flame is converted into Fe^{2}O^{4}, and then behaves as the preceding.
(5) in borax. As magnetic iron ore.
(6) in mic. salt. As in borax.
(7) with carb. soda. —
(8) Special reactions. —
* * * * *
Mineral. Goethite
Formula. [...Fe]Ḣ.
Behavior
(1) in glass-bulb. Evolves water.
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. As specular iron.
(5) in borax. As specular iron.
(6) in mic. salt. As in borax.
(7) with carb. soda. —
(8) Special reactions. —
* * * * *
Mineral. Franklinite
Formula. ([.Fe][.Zn][.Mn]) ([...Fe=][...Mn=]).
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. Forms a white incrustation on the charcoal, which moistened with cobalt solution assumes a green color.
(4) in forceps. V. In the blue flame fuses on edges and and becomes magnetic.
(5) in borax. Gives the iron and manganese reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Affords a considerable white incrustation of ZnO.
(8) Special reactions. Gives a strong manganese reaction with nitre and carbonate of soda.
* * * * *
Mineral. Ilmenite
Formula. [...Ti=] and [...Fe=].
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V. In reducing flame fuses on edges and becomes magnetic.
(5) in borax. Gives the iron reaction.
(6) in mic. salt. In oxidizing flame exhibits the iron reaction. In reducing flame assumes a deep brownish red color.
(7) with carb. soda. —
(8) Special reactions. —
* * * * *
Mineral. Chromic iron
Formula. [.Fe][...Cr=].
Behavior
(1) in glass-bulb. —
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. As the preceding.
(5) in borax. Dissolves slowly and gives the chromium reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. On platinum foil with nitre and carbonate of soda affords a yellow mass of chromate of potassa.
(8) Special reactions. —
* * * * *
Mineral. Lievrite
Formula. 3([.Fe][.Ca])^{3}[...Si] + 2[...Fe=][...Si].
Behavior
(1) in glass-bulb. Occasionally gives off some water and turns black.
(2) in open tube. —
(3) on charcoal. Fuses to a black globule, which in the reducing flame becomes magnetic.
(4) in forceps. I. In reducing flame is magnetic.
(5) in borax. Gives the iron reaction.
(6) in mic. salt. Gives the iron and silica reactions.
(7) with carb. soda. Fuses to a black opaque bead.
(8) Special reactions. Generally gives the manganese reaction with nitre and carbonate of soda.
* * * * *
Mineral. Chloropal
Formula. [...Fe=][...Si]^{2} + 3Ḣ.
Behavior
(1) in glass-bulb. Decrepitates more or less, gives off much water and turns black.
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V. Loses color and turns black.
(5) in borax. Gives the iron reaction.
(6) in mic. salt. Gives the iron and silica reaction.
(7) with carb. soda. Fuses to a transparent green glass.
(8) Special reactions. —
* * * * *
Mineral. Green earth
Formula. [...Si],[.Fe],[...Al=],[.Na],K,Ḣ, etc.
Behavior
(1) in glass-bulb. Gives off water and becomes darker in color.
(2) in open tube. —
(3) on charcoal. —
(4) in forceps. V. In reducing flame fuses on edges and colors the outer flame yellow ([.Na]) or violet (K).
(5) in borax. As the preceding.
(6) in mic. salt. As the preceding.
(7) with carb. soda. Forms a slaggy mass.
(8) Special reactions. —
* * * * *
Mineral. Siderite
Formula. [.Fe][..C].
Behavior
(1) in glass-bulb. Occasionally decrepitates. Gives off CO^{2} and turns black and magnetic.
(2) in open tube. —
(3) on charcoal. As in glass bulb.
(4) in forceps. Behaves similarly to the magnetic oxide.
(5) in borax. Gives the iron and manganese reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Behaves as an oxide. With nitre and carbonate of soda on platinum generally gives the manganese reaction.
(8) Special reactions. In acid dissolves with effervescense.
* * * * *
Mineral. Copperas
Formula. [.Fe][...S] + 7Ḣ.
Behavior
(1) in glass-bulb. Gives off water, and, when strongly heated, SO^{2} and SO^{3}, which reddens litmus paper.
(2) in open tube. Evolves water and SO^{2}, which may be recognized by its odor.
(3) on charcoal. Loses water and SO^{2}, and is converted into [...Fe=].
(4) in forceps. Gives off H and SO^{2}, and then behaves as the magnetic oxide.
(5) in borax. The roasted mineral affords an iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. Forms sulphide of sodium and oxide of iron. The former is absorbed into the charcoal, and if cut out and laid upon silver and moistened gives the S reaction.
(8) Special reactions. If dissolved in water, and a strip of silver-foil be introduced into the solution, the metal remains untarnished.
* * * * *
Mineral. Vivianite
Formula. [.Fe]^{3}[.....P] + 8Ḣ.
Behavior
(1) in glass-bulb. Gives off water.
(2) in open tube. —
(3) on charcoal. Froths up and then fuses to a grey metallic bead.
(4) in forceps. As on charcoal. Singes flame green ([.....P]).
(5) in borax. Gives the iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. In reducing flame becomes magnetic and fuses to a black saggy mass.
(8) Special reactions. —
* * * * *
Mineral. Iriphyline
Formula. ([.Fe][.Mn][.Li])^{3}[.....P].
Behavior
(1) in glass-bulb. Gives off water, having an alkaline reaction, and assumes a metallic lustre resembling graphite.
(2) in open tube. —
(3) on charcoal. Fuses readily to a black magnetic bead with a metallic lustre.
(4) in forceps. I. On platinum wire colors the flame crimson ([.Li]) and green ([.....P]), towards the point fuses to a black magnetic bead.
(5) in borax. Gives the iron and manganese reactions.
(6) in mic. salt. Gives the iron reaction which overpowers that of the manganese.
(7) with carb. soda. Forms an infusible porous mass, which under the reducing flame becomes magnetic.
(8) Special reactions. Gives the manganese reaction with nitre and carbonate of soda on platinum foil.
* * * * *
Mineral. Scorodite
Formula. [...Fe=][.....As] + 4Ḣ.
Behavior
(1) in glass-bulb. Evolves water.
(2) in open tube. Gives off water and AsO^{3}.
(3) on charcoal. Emits arsenical fume and in the reducing flame fuses to a magnetic mass having a metallic lustre.
(4) in forceps. I. As on charcoal. Colors the outer flame blue.
(5) in borax. The roasted mineral gives an iron reaction.
(6) in mic. salt. As in borax.
(7) with carb. soda. As alone on charcoal.
(8) Special reactions. Gives the arsenic reactions.
* * * * *
Mineral. Cube ore
Formula. [.Fe]^{3}[.....As] + [...Fe=]^{3}[.....As]^{2} + 18Ḣ.
Behavior
(1) in glass-bulb. Evolves much water.
(2) in open tube. As the preceding.
(3) on charcoal. As the preceding.
(4) in forceps. As the preceding.
(5) in borax. As the preceding.
(6) in mic. salt. As in borax.
(7) with carb. soda. As the preceding.
(8) Special reactions. As the preceding.
* * * * *
MANGANESE.
* * * * *
Mineral. Manganblende
Formula. MnS.
Behavior
(1) in glass-bulb. —
(2) in open tube. Gives off SO^{2} and becomes greyish green on surface.
(3) on charcoal. Is slowly roasted and converted into oxide.
(4) in forceps. V.
(5) in borax. The roasted mineral gives a strong manganese reaction.
(6) in mic. salt. In the unroasted state, dissolves with much ebullition and detonation due to elimination of sulphide of phosphorus. The bead then exhibits the characteristic violet color of manganese. |
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