Sjögrenite , Pyroaurite Locality: Palabora mine, Loolekop, Phalaborwa , Limpopo Province , South Africa ( Locality at mindat.org ) The sjögrenite/pyroaurite is green, so that’s the small green crystals – the two species are polymorphous so only an XRD or EDS can tell the difference. The orange coloured platy crystals are a weird phlogopite, I am told. Marty's label indicated sjogrenite first in capital letters, indicating he probably got it from somebody who knew which was predominant. Even from Langban, this would be a good specimen for the species with bright lustre and good-sized crystals. From South Africa...a very interesting specimen as I cannot find reference to the species occuring in South Africa yet, on MinDat (but it was verified by Dr. Bruce Cairncross via email, and he has similar examples). Palabora is a copper mine in the north-eastern corner of South Africa, close to the Mozambique and Zimbabwe borders. 6 x 3.4 x 2.6 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Pyroaurite
Pyroaurite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Mg₆Fe³⁺₂(CO₃)(OH)₁₆·4H₂O.
It crystallizes in the hexagonal crystal system (space group R3m). It is a member of the Hydrotalcite structural group.
Key properties: Mohs hardness 2.5; specific gravity 2.13; Waxy to vitreous, may be pearly luster; optically uniaxial.
IMA symbol Pya, IMA status: approved, named in 1865.
Found in low-temperature hydrothermal veins; in serpentinite and ophiolites; an authigenic weathering product.
It is found associated with Sjögrenite, calcite, magnesite, aragonite, hydromagnesite, artinite, dolomite, brucite, clinopyroxene, olivine, talc, phlogopite, spinel.
Its name comes from the Greek for fire and gold, for the golden yellow color developed on heating.