Whiteite-(CaMgMg)

whiteite-(CaMgMg)

crandallite

fluorwavellite

montgomeryite

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Formula: CaMg3Al2(PO4)4(OH)2.8H2O
Hydrated phosphate containing hydroxyl, jahnsite group, whiteite subgroup
Specific gravity: 2.48
Hardness: 4
Colour: Colourless
Environments

Hydrothermal environments

Whiteite-(CaMgMg) is a low temperature, secondary mineral formed as a result of hydrothermal alteration and approved in 2016 (Mindat).

Localities

The type locality, the Argentum Mining Co. mine, Candelaria Mining District, Mineral county, Nevada, USA, is the only locality where whiteite-(CaMgMg) has been reported to date (July 2021). The mine was historically one of the largest silver mines in the area, but Candelaria is now a ghost town. Primary ore consisted mainly of pyrite and sphalerite and minor galena, chalcopyrite, and arsenopyrite in a gangue of altered country rock, quartz and dolomite. Oxidised ore was composed predominantly of limonite and manganese oxide with small amounts of bindheimite, anglesite, smithsonite and cerussite. Whiteite-(CaMgMg) was collected from blocks containing hydrothermally altered phosphate nodules in a berm placed to block access to the Northern Belle pit and in a graded area adjacent to the berm. Whiteite-(CaMgMg) has not been found in situ. The mineral occurs in seams in dark-coloured massive quartz with embedded pyrite. Other secondary species observed in direct association with whiteite-(CaMgMg) are crandallite, fluorwavellite, montgomeryite and variscite/metavariscite. Other secondary phases in the same general assemblage include collinsite, gordonite, overite and whitlockite. Whiteite-(CaMgMg) is a low temperature, secondary mineral presumed to have formed as a result of hydrothermal alteration. A major serpentinite body in proximity to the deposit shows evidence of intense hydrothermal alteration, and this is believed to be the source of the Mg in the secondary phases, including whiteite-(CaMgMg) (CM 54.1513-1523).

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