Volltext Seite (XML)
3 T 4 Siliceous Genus. Its fraöure, imperfedtly conchoidal, inclining to the even. Fragments, 2.3. Its hardnefs, 9. I ts fp. gr. 2,33, by my llläi • The fpecimen of Lefke K. 33, melted ati^i 0 , into a fpongy, yellowifli grey tumefied femi- tranfparent mafs. Hence I confider it as fpecifi- cally different from jafpers. The colour of that I employed was lavender blue, and feemed per- fedtly pure. Mr. Peithner called it porcellanite, which name ihould be continued, not to confound this ftone with genuine jafpers. 35th Species. Heliotropium, Its colour is generally intermediate between grafs and leek green, fometimes dark mountain green, fometimes lighter, or approaching to a blackifh green, and moftly dotted or fpotted with olive green, ochre yellow, or blood red fpots of jafper. .Amorphous. Luftre, 1.0. Tranfparency, 2.1, fometimes fcarcely 1. Its fradture conchoidal, fometimes flat or im- perfedf, or mixed with the coarfe fplintery. Fragments, 3. Its hardnefs from 10 to 11. Its fp. gr. 2,62 to 2,7, In Mr. Lavoifer’s experiments, it was fcarcely melted even by pure air. In mine the dark green of Lefke O. 380, whofe fp. gr, was 2,681, became