GEF.Y COPPER-ORE. 123 It occurs rarely with a tempered-steel coloured tarnish. It occurs massive, disseminated, seldom in membranes, and often also crystallised : its crystallisations aie the following: 1. Tetrahedron, or simple three-sided pyramid*, fig. 102. which presents the following varieties: a. Truncated on the angles -|*, fig. 163.; or on the edges J, fig. 164. b. Bevelled on the edges ||, fig. 165. When the bevelling edges increase so much as to cause the original planes of the tetrahedron to dis appear, a tetrahedron is formed, in which each plane is divided into three, or there is formed on each of the planes a very obtuse acumination §, fig. 166. o. Each of the angles of the tetrahedron very flatly acuminated with tliree planes, fig. 167.. sometimes the edges of the tetrahedron are bevelled at the same time ^f, and also the summits and edges of the acuminations **. When the acuminating planes increase so much, that the original faces of the tetrahe dron disappear, there is formed 2. The rhoinboidal or garnet dodecahedron, fig 168. 3. When the truncations on the angles of the tetra hedron * Cuivre gris primitif, Hauy. 'X Cuivre gris epointe, Hauy. £ Cuivre gris cubo-tctraedre, Hauy. }[ Cuivre grin encadre, Hauy. £ Cuivre gris dodecacdre, Hauy. % Cuivre gris apopiiane t Hauy; Cuivre gris progrossif, Hauy. ** Cuivre gris idciitique, Ilauy.