| Tetrahedrite, blende, diamond, boracite and pharmacosiderite are substances which crystallize in this class. |
| In external form these crystals are cubic with inclined hemihedrism, the symmetry being the same as in blende and tetrahedrite. |
| The blende is first roasted in huge furnaces specially built for the purpose. |
| Masses of sulphuret of zinc, in the form of blende, were noticed at this locality. |
| The ores are argentiferous galena, accompanied by considerable amounts of blende and pyrites, all oxidized near the surface. |
| The gold is also often visible to the naked eye in all the associated minerals, and particularly in the mispickel and blende. |
