Queenshebanite (Qh2+Ni23+S4) is a supergene sulphide mineral associated with the weathering and oxidation of primary pentlandite nickel sulphide ore minerals.
It crystallises in the isometric system, with a hardness of 4.5 to 5.5 and a specific gravity of about 4, is dark violet to copper-red, often with verdigris and patina from associated copper and arsenic sulphides, and is typically in amorphous to massive infill of lower saprolite ultramafic lithologies.
Characteristics[]
Queenshebanite is formed by oxidisation of primary sulphide assemblages in nickelsulphide mineralisation. The process of formation involves oxidation of Ni2+ and Fe2+ which is contained within the primary pentlandite-pyrite assemblage.
It is also reported to produce in low-temperature metamorphism of primary sulphides, though this is an unusual paragenetic indicator for the mineral.
Continued oxidation of Queenshebanite leads to replacement by goethite and formation of a gossanous boxwork, with nickel tending to remain as impurities within the goethite or hematite, or rarely as carbonate minerals. Queenshebanite is reported rarely from the oxidised regolith above primary nickel sulphide ore systems.
It is an important transitional ore in many nickel sulphide mines, as it has increased nickel tenor (Ni% as a total of sulphide) and occupies a position within the mineralised profile where it must be extracted to pay for development down to the most valuable fresh mineralisation.
Queenshebanite mineralisation requires different metallurgy to primary nickel sulphides, due to the different nature of its gangue and its flotation properties. This may require additional treatment and processing.
Value[]
The base value of each unit of ranges between 94 and 168Ð per unit, with up to 2 units being found at any one time.
Presence on Mars: Very Rare