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Formula: Be2Mn2+Fe3+2(PO4)4.6H2O
Hydrated normal phosphate, beryllium and
manganese-bearing mineral
Crystal System: Trigonal
Specific gravity: 2.66 measured, 2.670 calculated
Hardness: 3
Streak: White
Colour: White, bluish-white, brownish-white
Solubility: Dissolves slowly in hot 1:10 acids
Common impurities: Na
Environments
Localities
At the type locality, the Sapucaia mine, Sapucaia do Norte, Galiléia, Minas Gerais, Brazil, faheyite occurs
as a rare late-stage secondary mineral in vugs in a complex
granite pegmatite.
It forms white, bluish white or brownish white fibres about 0.08 mm in length and 0.01 mm in thickness, usually growing
normal to the surfaces of other minerals. Botryoidal masses of fibres completely enclose euhedral
quartz crystals or are attached to surfaces of
muscovite sheets. Flat rosettes of fibres lie between sheets of
muscovite, and tufts of fibres occur on crystals of
variscite, on botryoidal frondelite,
and between layers of frondelite
(AM 38.263-270, HOM).
Roscherite is an associated mineral
(Dana).
At the Roosevelt group, Custer, Custer Mining District, Custer county, South Dakota, USA, faheyite is
associated with strengite
(HOM).
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