An isometric mineral, NiAsS ; cobaltite group; massive; sp gr, 5.9 to 6.0; in sulfide veins intergrown with maucherite, nickeline, and chalcopyrite at the Garson and Falconbridge Mines, Sudbury, ON, Can.; with cobaltite and rammelsbergite in the silver-arsenide ores of Cobalt, ON, Can.; a source of nickel.