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Formula: Ca9Mn2+4Al2(PO4)10(OH)2
Anhydrous phosphate containing hydroxyl, manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.24 to 3.35 measured, 3.355 calculated
Hardness: 5
Streak: White
Colour: Pale yellow
Environments
Samuelsonite occurs as a secondary mineral in complex zoned
granite pegmatites
(Webmin).
Localities
At the Buranga pegmatite, Muhororo, Ngororero District, Western Province, Rwanda, samuelsonite is associated with
trolleite, bertossaite,
scorzalite, apatite,
burangaite and gatumbaite
(HOM).
At the type locality, the Palermo No. 1 Mine, Groton, Grafton county, New Hampshire, USA, samuelsonite is found
embedded in black ferric and manganic
oxides and in pockets in
whitlockite-carbonate-rich apatite rock
(Dana). Associated minerals include childrenite,
hydroxylapatite, arrojadite,
whitlockite, carbonate-rich apatite
and laueite. The samuelsonite appears to have crystallised towards the end
of the paragnesis, and it is locally replaced by laueite crystals
(AM 60.957, HOM).
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