Ores of Nickel
Millerite, NiS, Ni . 64.4, S . 35.6.—
H = 3.0-3.5, G = 5.2-5.6.
Color, brass-yellow. Brittle. Before the Bp. on Ch. it fuses to a magnetic, metallic globule. The roasted mineral gives in the borax bead the color reaction characteristic of nickel, and sometimes that of cobalt, which is often associated with it.
Niccolite, NiAs, Ni . 44, As . 56.—
H = 5.0-5.5, G = 7.35-7.67.
Color, pale copper-red. Lustre, metallic. Very brittle. Heated in an ignition tube yields a copious sublimate of arsenious oxide, the residue falling to a greenish powder. Before the Bp. on Ch. fuses to a white brittle globule emitting arsenical fumes. In borax bead gives color characteristic of nickel. Frequently in this mineral a portion of the arsenic is replaced by antimony.