Magnesium Chromite, MgO.Cr₂O₃

Magnesium Chromite, MgO.Cr₂O₃, has been obtained by fusion of the mixed oxides. It yields green octahedra harder than quartz and of density 4.415 at 16° C. and 4.6 at 20° C. Several other compounds of magnesium and chromic oxides are known which may be represented by the formulae: MgO.2Cr₂O₃; 2MgO.Cr₂O₃; 3MgO.2Cr₂O₃; 5MgO.4Cr₂O₃.