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Phosphate

Arrojadite-(KFe)

(KNa)Fe²⁺(CaNa₂)Fe²⁺₁₃Al(PO₄)₁₁(PO₃OH)(OH)₂
Hardness5
Crystal systemMonoclinic
ClassPhosphate
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Arrojadite-(KFe)

Arrojadite-(KFe) is an IMA-recognized mineral species in the phosphate class, with the chemical formula (KNa)Fe²⁺(CaNa₂)Fe²⁺₁₃Al(PO₄)₁₁(PO₃OH)(OH)₂.

It crystallizes in the monoclinic crystal system (space group B2/b). It is a member of the Arrojadite structural group.

Key properties: Mohs hardness 5; specific gravity 3.527; White streak; Vitreous luster; optically biaxial.

IMA symbol Ajd-KFe, IMA status: approved, named in 1925.

A high-temperature (≈ 800 °C) primary mineral in granite pegmatites.

It is found associated with Graftonite, cassiterite, spodumene, beryl, muscovite (Nickel Plate mine).

Arrojadite indicates a member of the group with Fe2+ dominant at the M site; two suffixes indicate the dominant cation of the dominant valence state at the A and B sites.

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 A minerals or help write this entry.