CLASSY PUMICE. £85 First Subspecies. Glassy Pumice. Glasiger Bimstein, Werner # Karsten. External Characters. Its colour is smoke-grey, of different degrees of inten sity ; also ash-grey, which sometimes inclines to greyish- white. It occurs vesicular, and capillary in the vesicular ca vities. Internally the principal fracture is glistening and pearly, the cross fracture shining, and nearly vitreous. The principal fracture is promiscuous fibrous; the cross fracture small and imperfect conchoidal, inclining to uneven. The fragments are angular, and blunt-edged. It is sometimes translucent, sometimes only translucent on the edges. It is intermediate between hard and semi-hard. It is very brittle. It is pretty easily frangible. It feels very rough, sharp, and meagre ; and Is light or swimming. Specific gravity, 0.378 to 1.444, Hoffmann. Gcognoslic and Geographic Situations. It occurs in beds, along with common pumice and ob sidian, in the Lipari islands, and in the islands ot Santo- J 'ni and Milo, in the Grecian Archipelago. Observations.
