COMMON WHITE LEAD-ORE. 879 on the lateral planes. Sometimes the summits and edges of the acumination are truncated. S. Long acicular and capillary crystals, which arc columnarly aggregated. 9. It accurs also in twin and triple crystals. The crystals are usually small and very small; seldon* middle-sized. The crystals occur sometimes single, more frequently columnarly and scopiformly, or promiscuously aggrega ted. Externally, it alternates from specular splendent to glistening. Internally, it alternates from highly splendent to glist ening, and the lustre is adamantine, sometimes inclining to semimetallic, sometimes to resinous. The fracture is small conchoidal, which sometimes passes into uneven and splintery ; also concealed foliated . when the cleavage can be detected it appears five-fold, four of the folia appearing to be parallel with the sides of an octahedron, and the fifth parallel with the common base of the octahedron. The fragments are indeterminate angular. It alternates from translucent to transparent; and it refracts double in a high degree. It is soft. « It is brittle. It is very easily frangible. It is heavy. Specific gravity, 6 480, from Leadhills, according to Klaproth; 7.2357, Chevenix; G.0717,-6,5566, H axi y >' 6.255, Karsten; 6.P00, Ullman. Chemicol