Category Phosphate minerals Dana classification 38.2.3.6 | Strunz classification 8.AC.10 Crystal system Monoclinic | |
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Formula(repeating unit) (Na,Ca)Mn(Fe,Mn,Fe,Mg)2(PO4)3 Crystal class Prismatic (2/m)(same H-M symbol) | ||
Alluaudite is a relatively common alkaline manganese iron phosphate mineral with formula (Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3. It occurs as metasomatic replacement in granitic pegmatites and within phosphatic nodules in shales.
It was first described in 1848 for an occurrence in Skellefteå, Västerbotten, Sweden. It was named by Alexis Damour after François Alluaud (II) (1778–1866).
References
Alluaudite Wikipedia(Text) CC BY-SA