Angarfite
Angarfite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaFe³⁺₅(PO₄)₄(OH)₄·4H₂O.
It crystallizes in the orthorhombic crystal system (space group C222_1).
Key properties: Mohs hardness 2.5; specific gravity 2.76; Pale brown streak; Vitreous luster; optically biaxial.
IMA symbol Agf, IMA status: approved, named in 2010.
Found in phosphate nodules in the intermediate zone of a granitic pegmatite by the reaction of Na-bearing hydrothermal solutions with primary triphylite.
It is found associated with Triphylite, lipscombite–barbosalite, jahnsite-(NaFeMg), bederite.
The name refers to the pegmatite body from which the first specimens were collected.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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