*62 
EARTHS. SILICEOUS. ss-QiiarUum. 
Found on barren comn’oris and lieaths: is very •eafily tslo'Jif** ' 
about when dry, but when wet is rather plaflic and yields i* 
the {irdTure of the hand. It is chieliy ufed ia the beds a»^ 
moulds where metals are call. 
lurtaria. Ill larger equal round tranfpait'nt wintifli grains. 
Arena canip'llris. Sjfi.Kat, xii. 3. p. 197. n. 
Arena quartzofa. Wall Jyst. min, l, p. 103. a. 3, 
2. .Aretta margaria. Sy/l. nat. xii. 3.^. 197, e. 5. 
Found on barren heaths asd woody commons, and is prioct' 
pally ufed in hour-g'alTes. 
aioBili.i. In very minute round tranfparcnt white grains. 
A. qnartz. rotund, diaph. hyal. Syji. nat. xii. ». i. 
A. quartz mobiblT. WalLfyiV. min. I . pAQl, «.l. 
Quicltfaitd, Sehmeijur luiner. 1.^. 336. 
1. A. quartz, venco volatilis. Syfi.aat. i. s.3. 
2. A. quartz, rotand. ssquai. Sfft. r.at. .1. «. 4. 
3. A. quartz, impalpab- SjH. nat. l . /S. 208. ». 2. 
Found in the fea and adjacent waftes, and is alfo thrown o'*' 
from iprings: when dry it is fo tight as to be driven about bf 
the winds and collefled into fand-banks, and often taken "P 
in vail; maffes by whirlwinds, overwhelming and fuffocatinS 
travellers and even whole villages: it is kcptcOmpaft by 
roots of the Elynrus arenarius, Ariindb arenarius, TriticuS* 
repens, and fome fpbeies of Willow. 
55* QUARTZUM. Confifting of filica, about ^ 
per cent, of alumina, and i per cent, of carbo' 
nate of lime: hard, lightidi, brittle, fhining i**' 
tcrnally, breaking into indeterminate fragment* 
with acute margins, more commonly parafiticah 
found in mountains of all ages, mouldering 
the air; not melting fay fire alone, but with lod^ 
running into a hard pellucid glafs. ^larf^' 
fbrosum. Diaphanous, whitilh, fibfous, with the fibres thicker 
parallel, of a common form. 
Born, ind fi/’. t.p.it, i,p.g2. 
Fibrous Quartz. Kir<wan. mineral. 1. p. 245. n^ar. 3, 
Found on the mountains in Hungary, and near 
bifchauvsx SiUfia •, exceeding rare. 
