MINERALOGY. 



fpecific gravity is 3.3. 

 ftituent parts are, 



According to Vauquelin, the con- 



and aflumes the appearance of a flag, 

 protli, the conftituent parts are, 



Alumine - - . 



Soda .... 



Fluoric acid and water 



According to Vauquelin, 



Cornelian'. See Chalcedony and Agate. 



Corundum, Corinden, Fr. The French mineralogifts clafs 

 as varieties of corundum the oriental ruby, x\\e fijpphire, and 

 emery. ( See thefe articles. ) Though they are principally 

 compofed of alumine, they are, excepting the diamond, the 

 hardeft of mineral fubftances, and nearly the heavieft of earthy 

 minerals, the fpecific gravity being from 3.87 to 4.28. 

 Common corundum, or adamantine fpar, has a greenifh-white 

 colour : it is fometimes pearl-grey, brown, or red. It is 

 tranflucent and fometimes nearly tranfparent, and is doubly 

 refrafting. It has a diftinft lamellar llrufture, and fplits 

 into rhomboids, the angles of which are 86 " 38' and 93° 22'. 

 (See Adamantine Spar.) This mineral is found im- 

 bedded in granite, like felfpar, in various parts of India, and 

 alfo in North America, and imbedded in micaceous fchifl: 

 in Italy. 



Cross-stone, Harmotom'e, Haiiy. See Zeolite. 



Cryolite, Alum'me fluatee, Fr. This mineral has 

 hitherto been found only in Well Greenland. It occurs in 

 two thin layers in gneifs. Its name is derived from the 

 Greek word denoting ice, becaufe this mineral melts almoll 

 like ice at a low heat. Its colours are pale greyilh-white, 

 fnow-white, and yellowifh-brown. It occurs mafiive and 

 difleminated. It has a (hining or gliftening vitreous luftre, 

 inclining to pearly, and is tranflucent. The ftrufture is im- 

 perfeftly lamellar, with joints in three direftions parallel to 

 the faces of a reftangular parallelopiped. It is fofter than 

 fluor fpar, and is eafily frangible. The fpecific gravity is 

 2.9. It becomes more tranflucent in water, but does not 

 melt. Before the blow-pipe it firll melts, then hardens, 



According to Kla- 



- 36 



40 



Columbite, an ore of tantalum. See Tantalite. 



Compact Felfpar. See Felspar, Addenda. 



Copper Niclcl. See Nickel-ores, Addenda. 



Copper-ores, (See Copper-ores, and Phosphate of 

 Copper, Addenda.) The following table of the annual 

 quantity of copper raifed in Europe is given in the laft 

 edition of Jamefon's Mineralogy, vol. iii. p. 196. The 

 authority is not ftated. 



Alumine 



Soda ... 



Fluoric acid and water 



21 



32 



47 



Crysoberyl, Cymophane, Haiiy. See Crysoberyl. 



Cube-ore, Arfemate of Iron, Per arfemate, Haiiy. See 

 Iron-ore. 



Cupreous Arfemate of Iron, Martial Arfemate of Copper. 

 See Copper-ores. 



Cyanite, or Kyamte ; Sappare, Saufliire ; Dorthene, 

 Haiiy. See Kyanite, Addenda. 



Datolite, (fee Datholite,) is compofed of boracic 

 acid, united with lime and filex. It occurs maflive and 

 cryilallized in oblique four-fided prifms, generally trun- 

 cated on the edges and angles. The primitive form of the 

 cryftal is ftated by Hanfmann to be an oblique four-fided 

 prifm, with angles of 77° 30' and 102° 30'. It gelatinizes 

 with acids. In the flame of a candle it becomes opaque 

 and friable. Before the blow-pipe it intumefces, and then 

 melts into a globule of a pale rofe-colour. 



Diallage, Smaragdit of Saufliire ; D'lallage verte, Haiiv. 

 Its colours are grafs-green and apple-green ; it occurs maf- 

 five and difleminated. The luftre is (hining, gliftening, and 

 pearly; it is tranflucent on the edges. Diallage has a 

 lamellar ftrufture, with a two-fold nearly reftangular 

 cleavage, only one of which is diftinft. It is rarely fo 

 hard as glafs. The fpecific gravity is 3. Before the 

 blow -pipe, it melts into a grey or greenifli enamel. Accord- 

 ing to Vauquelin, the conftituent parts are, 

 Silex 

 Magnefia 

 Alumine 



Lime ... 

 Chrome 



Iron . . - 



Copper 



Diallage is found in Corfica with fauflurite, and on 

 Mont Blanc in Switzerland ; alfo in Carinthia and Tran- 

 fylvania. The mixture of diallage and fauflTurite is named 

 Gabbro by the Italians, Euphotide by the French, and 

 Verde de Corfica duro by artifts. When cut and polilhed 

 it has a beautiful appearance, and is made into various articles 

 of ornament. 



Diallage Metalloide. See Bronzite, Hyperstene, 

 and Schiller Spar, Addenda. 



Diamond, Diamant. (See Diamond.) In addition to 

 the charafters of the diamond given under that article, it 

 may be proper to ftate, that befides the colours there enu- 

 merated, the diamond occurs fometimes blue, red, brown, 

 yellow, and green, with the following tranfitions. The 

 only variety of blue is indigo-bhie, which appears to pafs 

 into red. Of red, the varieties are rofe-red and cherry-red. 

 From the latter colour it pafles into olive-brown, and 

 yellowifli-brown, ochre-yellow, orange -yellow, wine-yeilow, 



and 



