1) Nickel mineral 
Krutovite is a cubic nickel diarsenide with a chemical composition of NiAs2 and a sulfur content of 0.02-0.34 weight percent (Vinogradova, et al., 1977). Krutovite is composed of nickel and arsenic with trace to minor amounts of cobalt, iron, copper, sulfur, and antimony (Vinogradova, et al., 1977). ==Geological occurrence== Krutovite occurs in th...