Nickeline

A minor ore of nickel. Nickeline is a mineral having composition NiAs and crystallizing in the hexagonal system. Crystals are rare, and nickeline usually occurs in massive aggregates with metallic luster and pale copper-red color. Because of the color, not the composition, it is called copper nickel. The hardness is 5.5 on Mohs scale and the specific gravity is 7.78. Nickeline is frequently associated with other nickel arsenides and sulfides in massive pyrrhotite. It is also found in vein deposits with cobalt and silver minerals, as in the silver mines of Saxony, Germany, and Cobalt, Ontario, Canada. See also Hardness scales; Nickeline; Pyrrhotite.