Faheyite
Faheyite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Be₂Mn²⁺Fe³⁺₂(PO₄)₄·6H₂O.
It crystallizes in the hexagonal crystal system (space group P3_121).
Key properties: specific gravity 2.66; optically uniaxial.
IMA symbol Fah, grandfathered status — known before the IMA’s founding, named in 1953.
A rare late-stage secondary mineral in a complex granite pegmatite (Sapucaia mine, Brazil).
It is found associated with Quartz, muscovite, variscite, frondelite (Sapucaia mine, Brazil); strengite (Roosevelt mine, South Dakota, USA).
The mineral was named to honor Joseph John Fahey (1901–1980), American analytical chemist, U.S. Geological Survey, Washington, D.C., USA.
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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