Breithauptite: Gemstone Information
Breithauptite is NiSb and forms thin tabular crystals of the hexagonal system though the massive variety provides the only material of ornamental interest. The colour is copper-red often with a violet tint, the hardness 5.5 and the SG 7.59–8.23. The RI is not obtainable by normal gemmological testing. Breithauptite occurs in hydrothermal calcite veins associated with cobalt–nickel–silver ores; most ornamental material coming from the Cobalt district, near Red Lake, Ontario, Canada – there are other locations in the Harz Mountains, Germany.