Muricakite, 93 Greyilh white, or verging to the dark pearl grey. It occurs partly Ihapelefs, partly in blunted fragments, partly cryftallized in rhoraboids, fmall or middle fized. The furface of the fragments is longitudinally ftreaked, that of the cryltals rough. External luftre greafy, 1. internal, pearly, 3. Tranfparency 3, 4. Fradture ftreight, foliated. Fragments rhom boidal. Prefents grofs-grained diftinft concretions. Hardnefs 8, brittle. Spec. grav. 2,480.’ It does not effervefce with acids until it äs pul- verized, and then but gently, though completely foluble therein; if previoufly heated, it will dif- folve more quickly. Heated to rednefs for half an hour, it does not decrepitate, but lofes 45 per ct. of its weight. In a porcelain heat, it vitrifies with the crucible, which it tranfpierces. By Mr. Klaproth’s analyfis, it contains 52 per ct. of mild calx, 45 of mild magnefia, and 3 of iron mixed with manganefe. 5 Berl. Beobacht. 55. It is found in Tyrol, and generally mixed with chlorite and talc. 5ih Spscies. Mixed with a notable proportion of argill or clay. Argillo-calcitei. ift Clafs. Readily difintegrable by expofure to the atmo- fyhere. Marls,