Whiteite-(CaMnMg)

whiteite-(CaMnMg)

roscherite

englishite

mitridatite

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Formula: CaMn2+Mg2Al2(PO4)4(OH)2.8H2O
Hydrated phosphate containing hydroxyl, whiteite subgroup, jahnsite group, manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.63 measured, 2.64 calculated
Hardness: 3½
Streak: White
Colour: Yellow, light lavender, pink
Environments

Pegmatites

Localities

At the type locality, the Tip Top mine, Fourmile, Custer Mining District, Custer county, South Dakota, USA, Whiteite-(CaMnMg) occurs in the outer-intermediate zone of the pegmatite, which consists of large crystals of microcline feldspar variety perthite, triphylite, quartz and muscovite, with minor amounts of beryl, albite, fluorapatite, elbaite and columbite-tantalite. Whiteite-(CaMnMg) is commonly associated with several other secondary phosphate minerals found along fracture surfaces in beryl and quartz. The paragenesis appears to be as follows: on early formed crusts of whitlockite and carbonate-rich apatite, montgomeryite crystals were deposited, locally with tiptopite. Following these, roscherite, englishite, whiteite-(CaMnMg) and mitridatite formed. Fairfieldite, where present, was the last to crystallise (CM 27.699-702).

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