Hureaulite

Hureaulite is a manganese phosphate with the formula Mn(2+)5(PO3OH)2(PO4)2*4H2O. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. It is sometimes written as huréaulite, but the IMA does not recommend this for English language text.

A complete series exists from lithiophilite, LiMn(2+)PO4 to triphylite, LiFe(2+)PO4, including hureaulite, strengite, FePO4*2H2O, stewartite, Mn(2+)Fe(3+)2(OH,PO4)2*8H2O, and sicklerite, (LiMn(2+),Fe(3+))PO4.

Environment
Hureaulite is a secondary mineral occurring in granite pegmatites. At the type locality it occurs in a zone of altered triphylite, LiMn(2+)PO4, in pegmatite. Typically occurs very late in the sequence of formation of secondary phosphate minerals. Associated at the type locality with vivianite, Fe(2+)3(PO4)2*8H2O; rockbridgeite, Fe(2+)Fe(3+)4(PO4)3(OH)5; heterosite, (Fe(3+),Mn(3+))PO4 and cacoxenite, Fe(3+)24AlO6(PO4)17(OH)12*17H2O. It can be synthesised; most natural hureaulites are Mn-rich compounds but extensive (Mn,Fe) solution is known for synthetic material.

Localities
The type locality is Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. Hureaulite is also found in a granite pegmatite known for its phosphates in the Aimorés pegmatite district, at the Cigana claim in Galiléia, Doce valley, Minas Gerais, Brazil, formerly known as the Jocão Mine.