EARTHS, argillaceous. 36. Bafaltes. 
t^nkatuu Compaft, fpontaneoufly falling into cruftofe fragments; 
the cruits fpliserical and concentric. 
Found with the B. columr.arisj is a little foftcr, with a paler 
tin^e, and crumbles more eafily. 
Soft, fragile, compaa, a little glolTy when rubbed, aat 
falling fpontaiieonny into fragtnents. 
Watken. Kir<waii, 223. '■Jhomtea chem. p. • 
Wacke. ^chmeiff. mineral. 1. p. ji8. 
Found in the mountain? of Boheinia and Saxsny, fometimes in 
entire ilr.ta, lomctiir.es in thi-i lasers under or between 
bafaltj colour cinereous, or greenilli, orblackifii, or yellaw- 
ifh, and often contains veins of metallic ores; lu lire none, 
fraflure even, texture earthy, opake, foft, eafily broken, and 
feels nightly greafy ; it withers by expofure to the atmof- 
phere, and then becomes more grey : frequently contaias 
black mica, but never olivin. 
^'-apezum. Hardilh, compaS:, imbibing water, growing reddi lit In the 
air and mouldering into lamellar pieces, crackling 
and breaking with explofion in the fire. 
Saxum impalpabile. Syst. nat. xii. 3. p. 72. ». 3. 
Corneus durus. Wall. fysi. min. i. p.^(:ii. n. 4. 
Trap. Kirnvan miner. 1. fi. ZZJ- Thomjon chem. 4. p. 134* 
Trapp. ScbmetJJir mineral, l. p. 183. 
1. Toadftone. Kirwan, i.p. zzq. 
Of a dark brownilh-grey colour, abounding with cavities fillel 
with cryllallized carbonate of lime, wliich from the de- 
ftrutlion or decompofition of the cryflals are often empty: 
contains filica 0,63. alumina 0,14. mild carbonate of lime 
0,07. oxyde of iron 0,16. IVtthering, 
2. Rovvley ragg, orTurilite. Kimnan. p.ztq. 
Of a black colour with numerous white dots, and black lamellx 
of bafaltinc, which give it a dark brownilh-grey appearance: 
found in large mafles, affefling a rhornboidal form, inciofing 
rounded pebbles of the fame fubliance: acquiring an ochr/ 
cruft by expofure to the air, and Ihining internally from a 
number of minute particles : heated in the open air it be- 
comes magnetic, and lofes about 3 percent, of its weight: 
it does not redden in the fire, but at 98°. melts into a po- 
rous black raafs, partly porcelane, partly enamel ; fraftttre 
nearly even, fine fplintery, often inclining to the conchoi- 
dal: contains lilica 475. aiuniina 325. oxyde of iron 200- 
PFithering. 
3. Whin-ftone. Kirwan miner. 1. p. 230. 
Of a blue or greyifti-black colour, and rather hard: found in 
detached fragments, or forming dykes in mines. 
Found in the mountains of Britain, ScanJina^ia, Sr.niizerland 
