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Phosphate

Graftonite-(Mn)

MnFe²⁺₂(PO₄)₂
Hardness5
Crystal systemMonoclinic
ClassPhosphate
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Graftonite-(Mn)

Graftonite-(Mn) is an IMA-recognized mineral species in the phosphate class, with the chemical formula MnFe²⁺₂(PO₄)₂.

It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Graftonite structural group.

Key properties: Mohs hardness 5; specific gravity 3.793; Colorless streak; Vitreous luster; optically biaxial.

IMA symbol Gft-Mn, IMA status: approved, named in 2017.

A common primary phosphate in beryl-columbite-phosphate subtype of zoned rare- element pegmatites related to anatectic melts.

It is found associated with Sarcopside, graftonite-(Ca), triphylite oxidized topotactically to ferrisicklerite and heterosite, alluaudite-group minerals, wolfeite, stanĕkite, whitlockite.

The suffix indicates the M1Mn-analogue of graftonite, M(1)FeM(2), M(3)Fe2(PO4)2.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more G minerals or help write this entry.