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. Varuträsk pegmatite, Skellefteå, Västerbotten. As thin crusts on varulite / hagendorfite.

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