Chrysolite

“ The country rock is granite and gneiss; the spur or ridge, where the mineral showed itself, a trap of chromiferous serpentine, or chrysolite formation. The strata developed is chrysolite rock, mixed with anthophyllite—a layer of micaceous rock—a seam of chalcedony—a stratum of chlorite, of the variety ripidolite, and a gangue of the same, which proves to be the usual matrix of the corundum. ”

“ In chrysoberyl, however, the beryllium exists as an aluminate, having the formula BeAl2O4, or BeO·Al2O3. The analysis of a specimen of Brazilian chrysoberyl gave alumina 78·10, beryllia 17·94, and ferric oxide 4·88%. The typical yellow colour of the stone inclines in many cases to pale green, occasionally passing into shades of dark green and brown. The iron usually present in the mineral seems responsible for the green colour. Chrysoberyl is often mistaken by its colour for chrysolite (q.v.) ”

“ You seal up the sum, full of wisdom, and perfect in beauty. 028:013 You were in Eden, the garden of God; every precious stone adorned you: ruby, topaz, emerald, chrysolite, onyx, jasper, sapphire{or, lapis lazuli}, turquoise, and beryl. Gold work of tambourines and of pipes was in you. In the day that you were created they were prepared. 028:014 You were the anointed cherub who covers: and I set you, [so that] you were on the holy mountain of God; you have walked up and down in the midst of the stones of fire. ”

“ Chrysoberyl also supplies the finest cat's-eyes (when the material is of a sufficiently fibrous or tubular structure) , and it further supplies the greenish-yellow stones frequently (though incorrectly) called "chrysolite" by jewelers. The material is very hard and reasonably tough and may be used in almost any suitable mounting.
Spinel. After chrysoberyl come the materials rated as about 8 in hardness. First and hardest of these is spinel, then comes true or precious topaz. The various spinels are very hard and tough stones. ”

“ CHRYSOPRASE (Gr. χρυσός, gold, and πράσον, leek) , a name applied by modern mineralogists to an apple-green variety of chalcedony or hornstone, used as an ornamental stone. The colour is due to the presence of nickel, probably in the form of a hydrous silicate. By exposure to a moderate heat, or to strong light, the chrysoprase becomes paler, or even colourless, but it may regain its colour by absorption of moisture. Chrysoprase is a mineral of rather limited distribution. ”

“ The principal chrome mineral is chromite, an oxide of chromium and iron. Chromite is a common minor constituent of basic igneous rocks of the peridotite and pyroxenite type. In these rocks it occurs both as disseminated grains, and as stringers, and large irregular masses which probably represent magmatic segregations. Alteration, and weathering of the parent rock, forming first serpentine and then residual clays, make the chromite bodies progressively richer and more available, by leaching out the soluble constituents of the rock leaving the chromite as residual concentrates. ”

“ The cleavage surfaces are often wavy or corrugated; and the same is true of all schistose rocks. Talc schist is easily distinguished from all other rocks by its light-grayish or greenish color, combined with its extreme softness, and its smooth, slippery feel.
Chlorite Schist.—The one essential constituent of this rock is chlorite, and the mineral specimen (No. 26) answers equally well as an example of the rock. As with talc schist, quartz, feldspar, and hydromica are rarely entirely absent. Besides these, the principal accessories are hornblende, magnetite, garnet, and epidote. ”

“ In all probability, in Nature many precious stones have formed in the same manner; and most mineralogists concur in the opinion that rock-crystals, consisting of nothing but silicic acid, and frequently weighing hundreds of pounds, have originated thus. It is almost certain that this formation from liquids into solid bodies has taken place in a large class of half-precious stones, such as quartz and pyrites, consisting likewise of nothing but silica—namely, agate, jasper, opal, chalcedony, chrysoprase, carnelian, heliotrope, and others. ”

“ In form, color and streak chromite resembles magnetite and franklinite. From the magnetite it is distinguished by being non-magnetic; from the franklinite, by being insoluble in hydrochloric acid, while the franklinite is soluble. Chromite furnishes practically all the chromium used in the arts and manufactures. It is a mineral associated with high temperatures, and therefore found in dark lavas, serpentine, and olivine. ”

“ It crystallizes in prisms which melt at 36° C. and boil at 201°.8 C. It is soluble in water, and the aqueous solution gives a blue coloration with ferric chloride. When treated with hydrochloric acid and potassium chlorate, no chlorinated quinones are obtained (M. S. Southworth, Ann. (1873) , 168, p. 271) , a behaviour which distinguishes it from ortho- and meta-cresol.
On the composition of commercial cresylic acid see A. H. Allen, Jour. Soc. Chem. Industry (1890) , 9, p. ”

“ Properties: Crystals exhibit remarkable twinning at times. Chrysoberyl is highly electric and when submitted to frictional agitation holds electricity for a long time. Not affected by acids. Under the blowpipe it is unaltered and infusible, but it fuses tardily with borax or microcosmic salt. The Alexandrite variety which, as Professor J. G. Dana says, bears the same relation to ordinary Chrysoberyl as Emerald to Beryl, displays curious changes of colour from leafy green to raspberry red in real and artificial lights. In the Zodiac: Chrysoberyl is under the Heavenly Pisces ”

“ A mineral known as pitchy copper-ore (Ger. Kupferpecherz) , and of some importance as an ore of copper, is usually classed as a variety of chrysocolla containing much admixed limonite. It is dark brown to black in colour, with a dull to glassy or resinous lustre, and resembles pitch in appearance. In thin sections it is translucent and optically isotropic, and recent examinations seem to prove that it is a homogeneous mineral and not a mechanical mixture of chrysocolla and limonite. ”

“ The theoretical formula FeCr2O4 corresponds with chromic oxide (Cr2O3) 68%, and ferrous oxide 32%; the ferrous oxide is, however, usually partly replaced by magnesia, and the chromic oxide by alumina and ferric oxide, so that there may be a gradual passage to picotite or chromespinel. Much of the material mined as ore does not contain more than 40 to 50% of chromic oxide. In the form of isolated grains the mineral is a characteristic constituent of ultrabasic igneous rocks, namely the peridotites and the serpentines which have resulted from their alteration. ”

“ Commercial cresol is at ordinary temperatures a liquid, and cannot be obtained in a crystalline state by freezing. Its boiling-point is from 198° to 203°; it is almost insoluble in strong ammonia, and, when 16 volumes are added, it then forms crystalline scales. On the other hand, carbolic acid is soluble in an equal volume of ammonia, and is then precipitated by the addition of 11⁄2 volume of water. Cresol is insoluble in small quantities of pure 6 per cent. soda solution; with a large excess, it forms crystalline scales ”

“ Hornblende schist sometimes passes into amphibolite, through the absence of quartz; and so does diorite, when the feldspar is deficient or wanting. Specimen 20, though small, is a typical example of this rock. The physical and chemical characteristics are essentially the same as for the mineral hornblende. The texture varies from coarsely to finely crystalline. The crystals are usually short and thick, and lie in all directions in the rock, which is thus very massive, the schistose texture being entirely wanting, and the stratification rarely showing in small masses. ”

“ But in recent years the designation cresylic acid has been applied to all sorts of mixtures of tar acids boiling above 190° C. Practically every maker of synthetic resins, antiseptics, and disinfectants has his own specifications for cresylic acid; it may be any mixture in almost any proportions of the three cresols, the six isomeric xylenols, and the higher boiling tar acids. Imports of crude cresylic acid are understood to be largely xylenol mixtures containing low percentages of the cresols. ”

“ After being kept for a time the chrysalides become a very dark brown, almost black, so that there is a temptation to throw them away as dead, since they show so little life; but on opening the hard, stick-like skin, the creature is found to be quite fresh. ”

“ The precipitate so obtained is a brown amorphous solid which readily oxidizes on exposure, and is decomposed by heat with liberation of hydrogen and formation of the sesquioxide. The sesquioxide, Cr2O3, occurs native, and can be artificially obtained in several different ways, e.g., by igniting the corresponding hydroxide, or chromium trioxide, or ammonium bichromate, or by passing the vapours of chromium oxychloride through a red-hot tube, or by ignition of mercurous chromate. ”

“ If a fragmental, compact, or vitreous rock is fissile, we use the term shaly; but a fissile, crystalline rock is described as schistose. The banded texture may occur with the fragmental,—banded sandstones, etc.; with the crystalline,—many gneisses, etc. (specimen 41) ; with the compact,—many slates, limestones, felsites, etc. (specimens 34, 42) ; with the vitreous,—banded obsidian, furnace slags, and some coal. The schistose texture may occur with the crystalline,—mica schist, etc. (specimen 43) ; and the shaly texture with the compact and fragmental, but rarely with the vitreous. ”

“ Carbolic acid may be confounded with cresol or with creasote, but the distinction between pure carbolic acid, pure cresol, and creasote is plain.
§ 232. Cresol (Cresylic Acid, Methyl-phenol) , —There [179] are three cresols—ortho-, meta-, and para-. Ordinary commercial cresol is a mixture of the three, but contains but little ortho-cresol; the more important properties of the pure cresols are set out in the following table:—
Pure ortho-, meta-, or para-cresol have been obtained by synthetical methods ”

“ It is described by Dioscorides and Pliny to be coloris herbæ segetis læte virentis, and porracei coloris; which is exactly what the Greeks called πράσινος. And Disscorides, in another Place, says, the best Chrysocolla was that which was κατακόρως πρασίζουσαν, satiatè porraceum. The Chrysocolla of the Antients was therefore very different from that of the Moderns: and was what, in a purer State, and larger Size, might in those Times very naturally be, and really was, accounted a Species of the Emerald. ”

“ Cold petroleum spirit dissolves cresol, but no crystalline scales can be separated out by a freezing mixture. Carbolic acid, on the contrary, is but sparingly soluble in cold petroleum, and a solution of carbolic acid in hot petroleum, when exposed to sudden cold produced by a freezing mixture, separates out crystals from the upper layer of liquid. Cresol is miscible with glycerin of specific gravity 1·258 in all proportions; 1 measure of glycerin mixed with 1 measure of cresol is completely precipitated by 1 measure of water. ”

“ Fig. 1. [1] This figure is given for the purpose of explaining the mode in which the fibrous disposition of chlorite is effected. The crystallized arrangement which is here so visible is generally observed in those chlorite fibres which occur in transparent quartz. I I have never observed it in chalcedony, yet there is little doubt that a similar disposition is equally the cause of the fibrous appearance so common in the specimens which have been figured in the former plates, the chief differences consisting in the smaller size and less perfect crystallization of the chlorite scales. ”

“ The carnelian was much esteemed by the ancients; and many fine engraved carnelians are preserved in different collections.
94. CHRYSOPRASE, an extremely hard kind of stone, of clear and delicate apple-green colour, is considered to be a kind of calcedony.
This beautiful mineral has hitherto been found only in the vicinity of Kosemitz, and in a few other parts of Lower Silesia. It is susceptible of a high polish, and is much prized by jewellers when its colour is deep and pure. ”

“ In solution it is precipitated yellow by the chloride of platinum, and yields, when not greatly diluted, a crystalline precipitate with perchloric acid. The crude salt of commerce contains chloride of sodium; and hence the odour disengaged by sulphuric acid may be mixed with that of chlorine or hydrochloric acid gas. When mixed with any vegetable or animal infusion by which it is coloured, crystals may sometimes be easily procured in a state of sufficient purity by filtration and evaporation. ”

“ Chrysostom had always been an ascetic liver, but he had not a robust frame, and he had been accustomed to wholesome food and the frequent use of the bath. Continuous travelling by night as well as day, the scorching sun, hot dust, hard bread, brackish water, and deprivation of the bath, threw him into a fever; but either from fear of the Isaurians, or of Leontius, bishop of Ancyra, in Galatia, one of his most virulent enemies, the journey was pursued without intermission till he arrived, more dead than alive, at Cæsarea, in Cappadocia. ”

“ Oxyhalogen derivatives of chromium are known, the oxychloride, CrO2Cl2, resulting on heating potassium bichromate and common salt with concentrated sulphuric acid. It distils over as a dark red liquid of boiling point 117° C., and is to be regarded as the acid chloride corresponding to chromic acid, CrO2 (OH) 2. It dissolves iodine and absorbs chlorine, and is decomposed by water with formation of chromic and hydrochloric acids; it takes fire in contact with sulphur, ammonia, alcohol, &c., and explodes in contact with phosphorus; it also acts as a powerful oxidizing agent. ”