CHROMITE, a member of the spinel group of minerals; an oxide of chromium and ferrous iron, It is the chief com mercial source of chromium and its compounds. It crystallizes in regular octahedra, but is usually found as grains or as granular to compact masses. In its iron-black colour with submetallic lustre and absence of cleavage it resembles magnetite (magnetic iron ore) in appearance, but differs from this in being only slightly if at all magnetic and in the brown colour of its powder. The hard ness is 51; specific gravity 4.5. The theoretical formula corresponds with chromic oxide 68%, and ferrous oxide 32%; the ferrous oxide is, however, usually partly replaced by magnesia, and the chromic oxide by alumina and ferric oxide, so that there may be a gradual passage to picotite or chrome-spinel. Much of the material mined as ore does not contain more than 40 to 50% of chromic oxide. The earliest worked deposits of chro mite were those in the serpentine of the Bare hills near Baltimore, Md. ; and it is now mined in Southern Rhodesia, Quebec, New Cal edonia, India, Greece, Asia Minor, Ural Mountains, California, etc. It abounds in Chester county, Pa., at Hoboken, N.J., and in various parts of North Carolina. Chrome-iron ore is largely used in the preparation of chromium compounds for use as pigments (chrome-yellow, etc.), and in calico-printing.