3 2 4. Siliceous Genus. 39th Species. Labradore Stone. Labradore Felfpar of Wer ner *. Its colour is of a light or dark grey, or bluilh, or blackilh grey; bur, in certain pofitlons and fpots rcfledtmg blue, purple, red, green, &c. In blunted fragments it chiefly oceurs. Its luftre, 2.3. _ Its tranfparency, 1.2.3. Itsfra&ure, ftreight foliated. Its fragments, 2. Rhomboidal, with four polifhed faces, or tenc^ng to that jfhape. ^ Sometimes without diftindt concretions ; fome- times with large or coarfe grained, rarely with thick lamellar. Its hardnefs, ro. Its fp. gr . f r0 m 2,67 to 2,6925. 4 At 130°, a fpecimcn of the bluifh grey whofe franlparency was barely 1, and its fp.gr 2,672, wh-ch I had from Mr. Woulfe, was barely glazed on the outfide ;*and at irr 0 the white parc leparatcd itfelf from the brown, and was melted. Tho brown was alfo imperfcdtly meltec* mto an opake porous brown porcelain. 1 rom this dißicult f ufibility, I conclude Labra dore to be fpecificallv different from common felfpars; the nature of the brown matter is not known, this ftone' having. never been analyzcd The green felfpar of Siberia, defcribed byMr. Bindheim, 5 Berl. Beob. p. 107, i s evidently a vanety of this fpecies. It differs onlv in the fol- * U r eru. Cronft. p. 149, lowing