MINERALOGY. 



acid obtained from this mineral when combined with lead 

 forms a beautiful yellow pigment, and is now an article of 

 commerce. 

 ■ CiiuoMATE of Lead, red lead-ore. See Lead-Ores. 



Chrvsocolla, Earthy Malachite, Crtore malachite cry- 

 focolle, Fr. SeeCopPEU-OnK. ,„ ^ , 



CluiYsOLXTE, Perulot rhrvfinthcFr. (See CHRYSOLITE.) 

 This crcm is the fofteft of the precious Hones ; its colours 

 change by heat. It is brought to Europe from the (hores 

 of the red fea. Jamefon. , , , 



CiiRYsopRAsE. Apple-green chalcedony coloured by 

 the oxvd of nickel. ( See Chrysoprase. ) It has hitherto 

 been found only in the vicinity of the towns of Glaflendorf, 

 Grochau, and Kofemutz, in Lower Silefia. It is foftcr 

 than common chalcedony. It is ufed in jewellery. 



CiMOLITE. See CiMOLlTE. 



Cix-VABAR, Mercurefulphure, Haiiy. (See Mercury- 

 Ores.) Befides the localities of cinnabar there enumerated, 

 various mines of cinnabar occur in New Spain. In the 

 kingdom of New Granada, cinnabar is found in three 

 different places in veins, and alfo in alluvial foil, mixed 

 with o-old. In Peru, cinnabar occurs in various parts, par- 

 ticularly near the town of Huancavelica, at the height of 

 twelve thoufand feet above the level of the fea. Cinnabar 

 is found in veins near to Sillacara, interfefting alpine 

 lime-ilone ; thefe veins, according to Humboldt, at prefent 

 furnifli all the mercury of Peru. 



CiNXAMON-STONE. This gem was originally found in 

 the fands of rivers in Ceylon. It has been claffed with 

 hyacinth, but is a variety of garnet. Its colours are, hya- 

 cinth-red inclining to orange-yellow. It is found in blunted- 

 angular or in roundilh pieces. It has a ihining vitreous 

 luftre approaching to fplendent. The frafture is flat and 

 fmall conchoidal. It is tranfparent or femi-tranfparent, 

 but gener:illy full of cracks. It fcratches quartz with 

 difficulty. When cut it feels rather greafy. The fpecific 

 gravity is 3.6.. According to Klaproth, the conftituent 

 parts arc, 



Silex . . . , 



Alumine - - - 



Lime .... 



Oxyd of iron 



38.80 

 21.25 



3J-25 

 6.50 



in others, it cxifts in the ftate of oxyd. According to Mr. 

 Jamefon, it would appear that the carbonated iron-ftones by 

 decompofition lofe their carbonic acid, and are in time con- 

 verted into the oxydated varieties. In thofe common clay 

 iron-ftones which have a yellow or brown llreak, the iron is in 

 the ftate of hydrate ; in thofe having a red ftreak in the 

 oxydated ftate, and in moft of the varieties having a grey 

 ftreak, the iron is carbonated. When the carbonated varie- 

 ties begin to decay they become foft, and affume a liver or 

 reddifh-brown colour. This fpecies of iron-ftone, befides 

 occurring in numerous thin ftrata alternating with coal-fhale 

 and fand-rtone in the coal formation, occurs in kidney-fhaped 

 and rounded nodules. The greateft repofitory of this ore 

 in Great Britain is in the coal baiin extending from Pem- 

 brokeftiire into Glamorganftiire, on the borders of the 

 Briftol Channel. 



Clay-slate, Argillaceous Schiflus. See Slate. 



Clay' -STONE is nearly connefted with bafaltic and por- 

 phyritic rocks of the trap formation. It forms the bafis 

 of clay porphyries. The colours of clay-ftone are blueifh 

 and yellowifli-grey or yellowifti-white, lavender-blue and 

 brownifti-red. It is fometimes fpotted and ftriped. It has 

 a line earthy frafture, fometimes inclining to flaty or con- 

 choidal. The fragments are angular and rather blunt- 

 edged. It is opaque, yields to the knife, and- is rather 

 eafily frangible. The fpecific gravity is 2.2. It occurs in 

 various parts of Scotland, in North Wales, and in Shrop- 

 ftiire. 



Clink-stone, Phnnolite, Porphyry-Jlate, Fclfpath compare 

 fonore, Fr. has moft frequently a greenifti-grey colour. It 

 occurs in beds of confiderable magnitude in rocks of the 

 trap formation. (See Trap.) The principal fracture is 

 flaty, with a fcaly afpeA and a gliftening pearly luftre. The 

 crofs frafture is fplintery and faintly glimmering. It occurs 

 columnar and tabular, is tranflucent on the edges, and eafily 

 frangible. The thin tables yield a metallic found when 

 ilruck. The fpecific gravity is 2.8. It melts before the 

 blow-pipe into a grey-coloured glafs. According to Kla- 

 proth, the conftituent parts are, 



97.80 



Before the blow-pipe, it fufes into a blackifli enamel. When 

 free from flaws it is of confiderable value. 



Clay', Porcelain Clay, Potters' Clay, and Slate Clay. See 

 Clay. 



Clay Iron-Jlone, Argillaceous Iron-Jlone ; Fer oxyde maf- 

 _^", Haiiy. (See Iron-ores.) The name has been inappro- 

 priately given to this fpecies of iron-ore, as it frequently 

 contains fcarcely any alumine or clay in its compofition. 

 The following analyfis of Defcotels, given in the Ann. de 

 Chemie for 18 12, N^ 251, will fliew how greatly this fpecies 

 of ore varies in its compofition. 



From Blancheland. 

 Oxyd of iron 54-0 



Oxyd of manganefe 2.4 

 Silex - - 1 2.0 



Alumine - . i.o 



Magnefia - 2.0 



Carbonic acid and ) 



water - - } ^4.0 20.0 32.0 



In thefe fpecimens, the iron was in the ftate of carbonate ; 



Silex 



Alumine - 



Lime 



Soda 



Oxyd of iron 



Manganefe 



Water 



57-25 



23.50 



2.75 



8.10 



3-25 



0.25 

 3.00 



98.10 



This mineral is regarded as principally compofed of com- 

 paft felfpar. It pafles into bafalt, with which rock it is 

 often aflociated. 



Coal, Black and Brown. ( See Coal, and Collie- 

 ries. ) The coal called by the Germans glance-coal is 

 defcribed in that article as uninflammable or Kilkenny coal. 

 For a further account of it, fee Glance-Coa/, Addenda. 



Cobalt-ores. (See Cobalt.) Earthy cobalt-ore has 

 been found in fand-lf one at Alderly-edge, in Chefliire ; and 

 other ores of cobalt have recently been difcovered in feveral 

 mines in Cornwall. 



CoccoLiTE, Pyroxene granuliform, Haiiy. A granular 

 variety of augit. (See Augit.) The colour is various 

 fliades of green. It occurs in flightly coherent granular 

 concretions, has a lamellar ftrufture, a fliining vitreous luf- 

 tre, is more or lefs tranflucent, and fcratches glafs. The 



fpecific 



