Boracite. 545 Cryftals always fmooth and fplendent j and are middle-fized and fmall. Internally its luftre is fhining which approaches to gliftenmg, and is intermediate between adamantine and vitreous. Fracture intermediate between imperfectly and fmall conchoidal, and fine grained uneven. Fragments indeterminately angular, not particu larly {harp edged. Commonly femitranfparent, feldom pafles into tranfparent. Semi-hard in a high degree, equal to that of fluor fpar. • Brittle. : Eafily frangible. : ?f r Not particularly heavy. n Specific gravity—According to Wejlrumh, 2,566, Chemical Charafler. It melt? without addition before the blow pipe. Constituent
