152 



EARTHS. SILICEOUS. 45. Pyromachus. 



QculuiCatl, diaphanous, of an im[ierfe6lly foliated texture, exhibit- 

 ing parallel fibres internally, breaking into fomevvhat 

 irregular fragments. 



Silex Oculas Cati. Syfi. nat> xii. 3./>. 69, n, 6. c. 



Achates plus minus opaca. Wall. jytt. l» p. 282. «. 20. 



Cat's eye. Kir^wan miner, \. p. 30 1, SchmeiJJer. l. p. 137, 



Cat's eye. Ihomfon chem. 3. f. 524. 



Found in Ceylon and Siberia^ of a near'y fquare figure, with 

 iharp edges and a good deal of briliiancv : colour grey, with 

 a tinge of green, yellow or white, in certain poiitions re-* 

 fledling a fplendid white like the eye of a Cat, fomctimcs 

 brown with a yellow or red tinge: its texture is {o compafTt^ 

 that the foliations arc hardly difcernible, and is fo hard as to 

 ftrike fire with Heel: fpecific gravity from 2,625. ^^ 2,660, 

 contains filica 94,90. alumina 2j00. lime I550, oxyde of 

 iron 0,25. Klaproth^ 



C^, 



sreui% 



striatUi\ 



MTetaceus, 



4$. PYROMACHUS. Confiding principally of 

 filica^ with a fmall portion of alumina and oxyde 

 of iron, and frequently a little carbonate of lime t 

 hard, femitranfparent, lightifh, of a conchoidal 

 texture, breaking into indeterminate very acuc- 

 angled fragments, rarely leparating into concen- 

 trically cruitofe fragments, with hardly any luHire, 

 found chiefly in flratarial mountains, and rarely 

 forming (Irata itfelf: not fufibie per ie before the 

 blowpipe. 



Greyifh, approaching to fubopake, and of a fomewhat 

 fplintery texture. 

 Silex marmoreus vagus. Syst.nat. xii. 3. p* 68, ». 3, 

 Silex cinereus. It. Wgcth. 73. 



Found detached in Lujace^ and on mount Mojfehurg in Weflro^ 

 gotht covered with a hard white marmoreous cruft : it ap- 

 proaches to a petrofiiex. 



White, of a texture approaching to fibrous, 

 Wall. fyst. min. i. / 266. n. 7. 

 Found on the cretaceous hills o^ England, 



Tinged, femitranfparent, of a perfe6lly conchoidal tex- 

 ture. 

 Silex vagus, Syst. not. xii. 3, />, t"] n, I. 

 Silex opacus. Wall. fyfL min, i. p% 2O2, «. 4. 



Silex communis, Cromt^ miner, oi^ 



