Properties: Green crystals of cubic, specific gravity 2.07, soluble in water, slightly soluble in acid and aqueous ammonia. Water solution is acidic.

Specification (%)

Index	High grade	First grade
Assay (Ni)	22.2%min	22%min
Co	0.003%max
Water-insoluble matter	0.002%max	0.003%max
Mg	0.005%max	0.015%max
Ca	0.005%max	0.01%max
Zn	0.0005%max	0.001%max
Pb	0.0005%max	0.001%max
Fe	0.0005%max	0.001%max
Cu	0.0005%max	0.001%max