BASALTIC HORNBLENDE. 9 0. Tie six-sided prism flatly acuminated at one ex tremity by three planes, which are set on the alternate lateral edges; on the other bevelled, the bevelling planes set on the opposite lateral edges *. 4. Six-sided prism, in wdiich two opposite lateral planes are broader than the others, and doubly acuminated on the extremities ; first, with four planes, which are set on those edges which one of the broader lateral planes always forms with an adjacent smaller one; and again acuminated , with four planes, which are set on the first, un der very obtuse angles -J-. The crystals ore small and middle sized, seldom large, and are imbedded, and all around crystallised. Their surfaces are smooth. The lustre of the principal fracture is splendent and vitreous, approaching to pearly; that of the cross frac ture is glistening. The principal fracture is perfect and straight foliated, with a double oblique angular cleavage; the cross frac ture is small-grained uneven. The fragments are indeterminate angular, and some times indistinctly rhomboidul. It is always opaque. It is semi-hard, inclining to soft. It is rather brittle. -a It is more easily frangible than the preceding subspe cies. Specific gravity, 3.158, 3.199, Karslcn. Chemical * Amnhibole ondeciinul, Hauy. r|* Amphibole surcoropost*, Ilauy.
