COBALTITE, a mineral with the composition CoAsS, cobalt sulpharsenide. It is found as granular to compact masses, and frequently as beautifully developed crystals, which have the same symmetry as the isomorphous mineral pyrite, being cubic with parallel hemihedrism. The usual form is a pentagonal-dodecahe dron with faces of the cube and octahedron. The colour is silver white with a reddish tinge, and the lustre brilliant and metallic, hence the old name cobalt-glance. The brilliant crystals from Tunaberg in Sodermanland, Sweden, and from Skutterud near Drammen in Norway are well known in mineral collections. Crys tals have also been found at Khetri in Rajputana, and under the name septa the mineral is used by Indian jewellers for producing a blue enamel on gold and silver ornaments.