EARTHS. SILICEOUS. 55. Quartzum. 165 



Found at Breiback on the Huchjlurg in the bifliopric ©f Cologne ^ 

 iw Iceland y Siveden, znd Hungary : colour diaphanous, gene- 

 rally white, fometimcs yellowilh or reddifli j and appearing 

 in the form of folid or hollow cones, or in that ot rofes, 

 cauliflowers, grapes, $cc. 



fragile. Of a common form and fplintery texture, not falling 



fpontancoufly into fragments. 

 i» Nearly opake. 



Quartz, opac. rupeft. Sy/t, nat xii. 3. p. 66. «. 4. 

 Quartzum fragile rigidum. Walljysf. \. p. 213. 

 Quartzum purum. Crcnji.riun. J'ect. 51, B, 



2. Diaphanous, milky-white. 



Quarzum ladleum. iN>y/. ««/. xii. 3. />, 65. «. 3. 

 Quartzum folid. opac, Wall fyft.\.p.z\'^. 



Found aJmoft every wherein the fiil'ures of rocks and mountains ; 

 It'metimes opake, foraetimes diaphanous, rarely femipellucid : 

 colour moflly wh:te, oltcntinus milky, frequently pale 

 greeniQi or red, 



fraiius^ Leek-green, diaphanous, of a coarfe fplintery texture. 



Achates pellucida. Wall./rft. i. p. 297. n. 18. 



Prafium. Kir<wan miner* \. p. 249. 



Smaragdmatt. Cronst. min.feil. 73. 2. 



Prafe. SchmeiJJer 1. />. 97. ^homj^n chem. 3. p. 519. 



Prafe. Jameijon mineral, i. p. 157. 



Found at Schivartxenhurg in Saxony^ in Finland, Silfria, and, 

 Bohemia 3 either in irregular mafle?, or cryftallized in 6fided 

 pyramids, or in fmall 6-lided tables fuperimpofed one on 

 the other, fometimes in flender needle-like cryltals : colour- 

 green of various degrees of denfity, fom-times yellowifh or 

 blueifh-green : when broken it is fhining and of a c> arfe (hi- 

 very texture, fometimes approaching to the imperteftly fmall 

 ponchoidal ; admits a degree of polifh, aiid is frequently 

 numbered among the gcina. 



pngue Qf a common form, IHghtly grea fy to the touch, ap- 



proaching to the minutely conchoidal texture, ncit 

 falling fpontancoufly iiUo fragments. 



■Pure Quartz. Kirnjuan miner, i. p, 242, 



Quartz. Schfneiffer mineral, i />. 92. 



Common Quartz. 'Jameijon inineral. l.jJ. 152. 



Quartz, Thomjon chem, '^. p 517. 



1. Pellucid. Quartz, hyal. Syft. nat, xii. 3,/>, 65. /z, \, 

 Quartzum pellucidum. Wall, Jy ft. 1.^.212. «, 3. 



2. Diaphauous. WulLjyft» i,p, 212. n. 2. 



3. Coloured. Syjt. nat, xii. 3. p. 65. r. 2, 

 Quartzum coloratum. WalLjyJt. i. /». 213. »• $< 



