3 2$ Slliceous Genus. -_Atr i6q b , it whitened, and barely concreted, withotu any fanher fign offufion. He>;ce it. is plain it is fpecifically difFerent from the other itones httherto calied felfpars; on this account, to avoid confounding it with thetn, I cail it petriiite. # 4ift Species. Felfite, or compadt Felfpar of Widenman Its colour is azure blue, or in fome parts bluifh white, or pal?, or deep brownifh, or blackifh green, or greenifh white. It is found amorphous, aflociated with quartz and mica; in larger or imaller malles in granite; the green chiefly in porphyries. The blue was lately difcovered near Krieglach- in Stiria, by Mr. Widenman. Its lultre, i. Its tranfparency, fcarcely i. Its f radtu re uneven, yet often approaching to the fine iplintery; in fome fpecimens a fine foli- ated texture may, though with fome difficulty, be perceived. Its fragments, z. Indeterminate. Gives a white ltreak. Its hardnefs, 9. Its fp. gr. not confiderable, that is, dces not amount to 4. Expofed to a blowpipe it whitens and bccomes rifty, but is infufibleper fe. _ This (tone I have not as yet feen, or at leaft diftinguifhed.'- * 1 Bergm. Journ. i 79 r, p. 345. And the note in p. 346. 4zd Species.