black copper-ore. 127 7. Black Copper-Ore. Schwarzerz, Werner. Minera Cupri grisea, (in part) Waller. Syst. Min. t. ii. p. 281. —Cuivrc gris, (in part), Hauy, t. iii. p. 357.—Graugiltigerz, Ileuss, b. ii. 3. s. 4.27-—Schwarzgiltigerz, Lud. b. i. s. 218. Id. Such. 2to tli. s. 185. Id. Bert. s. S9S. Id. Mohs, b. iii. s, 1 (j(').—Graugiltigerz, Leonhard, Tabel. s. 58.—Cuivre giis antimonie,' Brong. t. ii. p. 216.—Graugil/igerz, Karslen, Tabel. s. 62.—Schwarzgiltigerz, Hans. s. 74—Cuivre gris antimoniferc, Ilauy, Tabl. p. 87—Antimonial Grey Copper, Ailcin, 2d edit. p. 86. External Characters. Its colour is iron-black. It occurs massive, disseminated; and crystallised in the following figures: 1. Tetrahedron. a. Perfect. b. Bevelled on the edges, and the angles flatly acuminated with three planes, which are set on the lateral planes. c. The preceding figure, in which the summits ot the acuminations are truncated. 2. When the acuminations on the angles of the tetra hedron become so large that its original planes disappear, then a rhomboidal or garnet dodeca hedron is formed. The crystals are generally splendent, and are often in vested with a thin crust of copper-pyrites. Internally it is shining and splendent, and the lustre is metallic. The