Mineral chemistry and formation of awaruite and heazlewoodite in the Xerolivado chrome mine, Vourinos, Greece

The Serpentinite between the chromite bodies 4 and 5 of Xerolivado mine (Vourinos,Greece), contains sparselyvery small grains (<20μm) of awaruite (Fe0.91Cu0.06Co0.03Ni3) heazlewoodite (Ni2.91Fe0.06S2) magnetite and Copentlandite (Ni3.79Fe2.98Co2.38S8). The olivine contains 0.40 wt% NiO and 6.91 wt% FeO, while the serpentine 0.18 wt% NiO and 3.02 wt% FeO. The Co-content of awaruite is 1.31 wt% and that of heazlewoodite 0.12 wt%. Heazlewoodite is a product of the primary Copentlandite reduction, resulting from the serpentinization of the ultramafic rock. The Ni content of awaruite is derived both from olivine and from Copentlandite. The reducing environment resulting from serpentinization and the low sulphur fugacity, favour the formation of awaruite, heazlewoodite and magnetite.