Ores OF Chromium

Chromic Iron Ore, FeO . 32, Cr₂O₃ . 68.—Al₂O₃, Fe₂O₃, MnO, and MgO are commonly present. H = 5.5, G = 4.32-4.57. Occurs usually massive. Color, iron-black to brownish black. In many varieties strongly magnetic. Lustre, shining and somewhat metallic. Heated in an ignition tube, remains unchanged. Infusible before the Bp. on Ch. Before the Bp. on Ch. with Na₂CO₃ and KCN yields metallic iron. In borax bead it slowly dissolves to a clear transparent glass, which is a beautiful green when cool.