Mineral description : Alluaudite

Alluaudite as a thin crust, from Mangvalde, Portugal.

Mineral class Phosphates : Amblygonite - Pharmakosiderite group.
Chemical formula Na(Fe,Mn)PO4
Crystal system Monoclinic.
Habitus Massive, grainy or radiating crusts.
Cleavage  
Hardness 5-5.5
Density 3-4
Color Yellow when fresh, often dull yellow to black by oxidation.
Streak Yellowish brown.
Luster  
Description  
Occurance A secondary phosphate mineral.
Associates Varulite, Hagendorfite.
Notes The black oxidation is easily removed with hydrocloric acid, but take it easy not to destroy it with acid.
Type Locality: La Vilate quarry, Chanteloube, Haute-Vienne, France
Locations A rare mineral in Sweden.

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Last changed : 1998-09-13