82 



CHROME- STONE. 



state, and in loose earthy masses of a bright 

 green or yellowish-green colour. Opaque, 

 dull. S.G. 2-7. 



Comp. ( Al, -€-r, i^e) bi^ ; but rarely found 

 pure. 



Analysis from Silesia, by Zellner: 



Silica 58-50 



Oxide of chromium . . 2-00 

 Alumina .... 30-00 

 Peroxide of iron . . . 3-00 

 Water .... 6-25 



99-75 



BB infusible alone, but becomes paler in 

 colour : with borax forms an emerald-green 

 globule. 



Localities. In Unst, one of the Shetlands, 

 in a nearly pure state, in small fissures in 

 Chromateof Iron. — Foreign. Creuzot (Saone- 

 et-Loire) in France. Silesia. ' Mortenberg 

 in Sweden. Savoy and Piedmont in Ser- 

 pentine. See also Chrome-Stome. 



Name. From %g^A<.a, colour. 



Brit. Mus., Case 39. 



Chromb - STONE. The name sometimes 

 given to oxide of chrome or Chrome-ochre, 

 when it is so intimately mixed with the rock 

 in which it is contained as only to be se- 

 parated from it by chemical means. Such 

 mixtures are met with at Creuzot in France, 

 Waldenberg in Silesia, Mortenberg in Swe- 

 den and elsewhere. 



Chromeisenerz, iVaztmawn, G.Rose. See 

 Chromic Iron. 



Chromeishkstein. See Chromic Iron. 



Chromic Iron, or Chrome-iron-ore. 

 Cubical. Occurs crystalHzed in octahe- 

 drons, the primary form, but commonly 

 massive and disseminated in grains. Colour 

 iron-black to brownish-black, with a shining 

 siibmetallic lustre. Opaque, Streak broMai, 

 Brittle. Fracture imperfect conchoidal, and 

 uneven. Sometimes slightly magnetic. H. 

 5-5. S.G. 4-3. 



Comp. Fe -er, or (Fe Mg) (Al, -&r) 

 part of the protoxide of iron being replaced 

 by magnesia, and part of the oxide of 

 chromium by alumina, and perhaps also by 

 peroxide of iron. 



Analysis of crystallized Chrome-iron-ore 

 from Baltimore, by Ahich : 



Magnesia .... 7-52 

 Protoxide of iron . . 20*13 

 Oxide of chromium . . 60-04 

 Alumina . . . .11-77 

 Silica 0-36 



99-82 



CHRYSOBERYL. 



BB alone, infusible; but becomes mag- 

 netic in the inner flame. With borax fuses 

 with diffiulty, but completely, to a globule 

 which, on cooling, exhibits the emerald- 

 green of oxide of chromium, which becomes 

 most apparent after heating the bead in the 

 innerflame, especially with the addition of tin. 



Localities. Scotch. — Massive and crystal- 

 lized in Unst, one of the Shetland Islands, 

 at Swinaness, Haroldswick, Balta Sound, 

 Buness House, &c., and also in Fetlar, and 

 some of the other smaller islands. Near Port- 

 soy, Banffshire. Foreigyi. — Forms irregular 

 veins, in Serpentine, at Cassin, Departement 

 du Var, in France, (iulsen Mountains, near 

 Kraubat, in Styria. Silesia and Bohemia. 

 In the Eastern Urals. 



This ore is highly valuable as affording a 

 pigment which is used in oil, porcelain, and 

 water-colour painting. The ore used for 

 this purpose is chiefly procured from Balti- 

 more (in the Bare Hills), in the United 

 States, Drontheim, and the Shetland Is- 

 lands. 



Brit. Mus., Case 39. 



M. P. G. Principal floor. Wall-cases 13 

 (British); 19 (Foreign) ; 39 (Madras). 



ChrojVIIT, Haidinger, v. Kohell. Chro- 

 MiTE, Brooke §' Miller. See Chromic Iron, 



Chromsaures Blei, v. Leonhard. See 

 Crocoisite. 



Chrysoberyl. Rhombic. Colour aspara- 

 gus-green, grass-green, oil-green, greenish- 

 white, and yellowish-green; sometimes with 

 a bluish opalescence internally. Lustre vitre- 

 ous. Streak white. Fracture conchoidal, 

 uneven. Transparent to translucent. H. 8-5. 

 S.G. 3-5 to-3-8. 



Fig. 115. 



BB iinaltered alone; with borax, or salt 

 of y)hosphorus, fuses with great difficulty; 

 with soda, the surface is merely rendered 

 dull. 



Not acted upon by acids. 



Comp. (B-e + A15) or glucina 19-8, alu- 

 mina 80-2 -=100, 



Analysis from Brazil, by Awdejew. (S.G. 

 3-7337) : 



Alumina .... 78-10 



Glucina .... 17-9L 



Protoxide of iron . . 4-47 



100-15 



