FLINT GENUS. It occurs mod frequently in original, round, and angular grains alfo cryftallized, in acute, double, eight-fided pyramids, in which the lateral planes of the one are fet on the lateral planes of the other, arid the fummits are deeply and flatly acuminated by four planes, which are conformably-wife fet on the alternate edges. The cryftals often Ihew a tendency to form grains, and conversly the grains to form cryftals. The cryftals are always all around cryftallized and imbedded; .they are commonly fmall, feldom middle fized. The furface of the grains is rough, and dull, or weakly glimmering ; that of the cryftals is fmooth, leldom flightly ftreaked, and gliftiling. Internally i £ is ftiining, approaching to gliftiling, and the luftre is vitreous, which inclines a little to refinous. Frafture imperfe&ly and flat conchoidal, and in* clines fometimes to foliated. Fragments indeterminately angular, pretty fharp edged. It is tranflucenty femitranfparent, and fome varieties approach to tranfparent. Hard in a low degree. Btittle. Eafily frangible. Not particularly heavy, almoft approaching t0 light. Specific gravity 2,4^8, Brifson.—>2,464, Kirivan 2,455 t0 2 >49°» Klaproth,— 2,461, Karjlen. CbemM 1
