Pyritaceous Limeßone. _ 105 Tranfparency 1,0 1,5. Fra&ure curved foliated, in the grofs llaty. Fragments 2. Hardnefs 5 to 6. Very brittle. Spec. grav. 2,647* Hath fomewhat of a greafy feel. Effervefces ftrongly with acids. Heated to rednefs, it turns reddilh brown ; by a heat of 155 0 it is converted partly into a brown porceläin mafs, and partly into a reddilh brown glafs, which attacks the crucible. Its compofition is not yet known, and I had too little of it to allow a farther examination; but, from its aftion on the crucible, I think it probably contains magnefia, and a fntall propor- tion of argill and calx of iron. According to Mr. Karften, its fpec. grav. is intermediate between the heavy and not re- markably heavy. Lelke’s Catalogue, p. 273. Mr. Hoffman, however, did not find its fpec. grav. fo high. That which I examined was taken front the fpecimen in Lefke, O. 1499. It has hitherto been found only in Barman’s Grün, near Schwartzcnberg, and Konfberg, in Saxony, and in the Snara pit, in Norway. The filvery chalk, already mentioned, feems however nearly related to it. 7th Species. Combined with ntanganefe and iron *. Sidero Calcite. Braun fpath of Werner, fpath perle of Rome de Lille. * Karden in Lefke, p. 274. 1 Eergm. I. 1789, 190. 12 An. Cliv. 165. Colour