Hureaulite is a manganese phosphate with the formula Mn52+(PO3OH)2(PO4)2·4H2O. It is a manganese phosphate mineral occurring in granite pegmatites. It is a mineral consisting of a hydrous manganese phosphate having a yellowish, orange-red, rose, or grayish color, and occurring in prismatic monoclinic crystals or massive. It was named after the type locality of the mineral at Les Hureaux in Saint-Sylvestre, Limousin, France.
Hureaulite is an uncommon mineral that can be found in additional localities in France, Portugal, Germany, Sweden, Finland, the United States
- Category: Phosphate minerals
- Formula: Mn52+(PO3OH)2(PO4)24H2O
- Crystal system: Monoclinic
- Crystal class: Prismatic (2/m) (same H-M symbol)
Hureaulite forms nice clusters of crystals with a pink color. Although the crystals are usually small, they do provide a good sparkle and make for attractive specimens. It is a rare phosphate of manganese and iron, occurring in small monoclinic crystals of a yellowish-brown to red color at Hureaux, near Limoges, in France.
- Formula mass: 728.65 g/mol
- Color: Orange, red, yellow, brown, grey or nearly colorless
- Fracture: Uneven
- Tenacity: Brittle
- Mohs scale hardness: 3.5
- Luster: Vitreous to greasy
- Streak: Nearly white
- Diaphaneity: Transparent to translucent
- Specific gravity: 3.18 – 3.2 (measured), 3.23 (calculated)
- Optical properties: Biaxial (-)
Occurrence – A late-stage secondary mineral formed by alteration of primary phosphates in complex granite pegmatites. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France.
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.
Association: Lithiophilite, triphylite, heterosite, rockbridgeite, cacoxenite, vivianite, fairfieldite, dickinsonite, eosphorite, stewartite, strengite, phosphosiderite, roscherite, many rarer phosphates.