EARTHS. SILICEOUS. 55. Qiiavtzum, 165 
Found at Breihack on the Backjburg in the bifliopric of Cologne^ 
\n Iceland, i’vceden, ^!\di Hungary : colour tiiaphanou?, gene- 
rally v.hit-, lometnnes yellowifli or reddift j and appearing 
in the tonu of folid or hollow pones, o,r \n that of rofqs, 
cauliflowers, grapa-s &c. 
Of a common form and fplintery texture, not falling 
fporitani.oufly into fragments. 
1, Nearly opjl:e. 
Quartz opac. rupefl. xii. 3. p- fin. 
Q^artzum fragile rigiduin. H'cul.Jyst. y.p, 213. 
Quartzum paruni. Cronjl. nun- feet. 51, B. 
2. Diaphanous, milky-white. 
Quarzum lafteum. nat- Xii. 3. n. 3- 
Quarizum folid. opac. M ali Jyft. 1 . p. 2 1 3- 
Found almoft every wherein the fiiTures of rocks and mountsins ; 
f metimes ppake, fometimes diaphanous, rarely leinipellucid ; 
colour mollly wh'tc, oitcntinns miiky, frequently palq 
greeniflr or red, 
Leek-grcen, diaplianpus, of a coarfe fplintery tcxttire. 
Achates pcllucida. \Vull.j\Ji- i. p- 297. «• i®. 
Prafium. Kir^wan miner. 1. p, 249. ^ 
Smaragdmatt. Cronsl. min. fe 8 . 73. z. 
Prafe. Schmci(/er l. p. 97. Thainjo?! chem. 3. 5 ’ 9 - 
Prafe. Jarnei/on mineral. \ . p- 157. 
Found at Scinvarlzenpurg in Saxony, in Finland, Siberia, and 
Bohemia-, either in irregular malfer, or cryllallized in 6 -fldc 4 
pyramids, or in fmall 6-fidcd tables fuperiropofed one on 
the other, fometimes ip Herder needle-like cry Hals : colour 
green of various degrees of denfity, foiuetimes yellowilh or 
blucilh green ; when l■.toke^l it is fhining and of a coarfe flii- 
very texture, fometimes approaching to the iinperteaiy fmall 
conchoidal; adjnits a degree of polifh, anti is frequently 
numbered among the gems- 
Of a common form, flightly greafy to. the touch, ap- 
proaching to the minutely conchoidal texture, not 
falling fpontaneouliy into fragments. 
Pure Quartz. Kirnuan miner, i. p. 24^* 
Quartz. Sehmeijjer mineral, i. p. 92. 
Common Quartz. Jametfon mineral. \. p. t52. 
Quartz. Ihomjon chem. 3- p- 5 
i. Pellucid. Quartz, hyal. Syjt. nat. xii. 3./.. 63. «..i. 
Quartzum pellucidum. M all. Jyft. i . p, ziz. n, 3, 
3. Diaphauous. Wall, fyftt \tp, 212. n. z, 
3. Coloured. Syft. nat. xii. 3. p. 65. n. 2. 
Quartzum coloraium, W all.fyjt. i . p. zi-g. n. 3. 
