TUNGSTEN. 547 The crystals are middle-sized, small and very small, and are sometimes heaped on one another. The lateral planes of the crystals are smooth, the be- veiling planes are slightly transversely stieakcd , they are shining and splendent, and their lustre inclines to ada mantine. Internally it is shining, and the lustre is intermediate between vitreous and resinous, and sometimes inclines to adamantine. The fracture is imperfect foliated, with a fourfold clea vage parallel with the sides of an octahedron. The fragments are indeterminate angular, and rather blunt edged. It sometimes occurs in large, coarse, and small granu lar distinct concretions* with streaked and shining sur faces. It is more or less translucent, seldom semitransparent. It yields pretty easily to the knife. It is-rather brittle. t It is easily frangible. Specific gravity 5.800 to G.02S, Kirwan. 6-0665, Brit- son. 6.000, Gellert. 6.015 and 5.570, Klaproth. Chemical Characters. y ' It crackles before the blowpipe and becomes opaque, hut does not melt; with borax it forms a transparent or °paque white glass, according to the proportions of each. M m 2 Constituent