Ferrowyllieite

ferrowyllieite

wyllieite

rosemaryite

arrojadite-(KFe)

Images

Formula: NaNaFe2+(Fe2+Al)(PO4)3
Phosphate, wyllieite group, alluaudite supergroup, forms series with wyllieite and with rosemaryite
Crystal system: Monoclinic
Specific gravity: 3.601 measured, 3.68 calculated
Hardness: 4
Streak: Light grey
Colour: Greenish black, also dark bluish green, dark greenish grey, dark green, dark brown
Luminescence: Not fluorescent under UV
Environments

Pegmatites

Ferrowyllieite occurs as a primary phosphate in zoned granite pegmatites (HOM).

Localities

At the type locality, the Victory Mine, Custer, Custer Mining District, Custer County, South Dakota, USA, ferrowyllieite occurs as crude euhedral crystals, to 10 cm in size, in interlocking aggregates in large pods in the granite pegmatite. Associated minerals include arrojadite-(KFe), muscovite, schorl, plagioclase and quartz (HOM, Mindat).
Ferrowyllieite from the Victory Mine - Image

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