266 BARYTE FAMILY. 2. Preceding figure, in which the summit of the acti- mination is more or less deeply truncated. 3. N° 1. in which the edges between the lateral and acuminating planes are truncated. 4. Double six-sided pyramid. The crystals are middle-sized, small, and very small. I'.xternally it is glistening; internally it is shining or> the principal fracture, and glistening on the cross frac ture, and the lustre is resinous. I he principal fracture is intermediate between’ flori- form foliated, and narrow scopiform radiated ; the cross fracture uneven, inclining to splintery. The fragments are wedge-shaped, or indeterminate an gular. The massive varieties occur in thin wedge-shaped di stinct concretions, which are often very much grown to-, gether, and occasionally pass into coarse granular. It is translucent, rarely semi-transparent. It is soft, inclining to semi-hard ; scratches calearcous- spar, but is scratched by fluor-spar. It is brittle. It is easily frangible. It is heavy. Specific gravity, 4.271, Lichtcnbcrg. 4.361, Karslen. Chemical Characters. Before the blowpipe it decrepitates slightly, and melts readily into a white enamel; it is soluble, with eflervcs- cence, in diluted muriatic or nitric acid. Constituent