Matioliite

matioliite

crandallite

gormanite

souzalite

Images

Formula: NaMgAl5(PO4)4(OH)6.2H2O
Hydrated phosphate, dufrénite group, forms a series with burangaite
Crystal System: Monoclinic
Specific gravity: 2.948 calculated
Hardness: 5
Streak: White
Colour: Blue to colourless
Luminescence: Not fluorescent under UV
Environments

Pegmatites
Hydrothermal environments

Localities

At the type locality, the Gentil claim, Mendes Pimentel, Minas Gerais, Brazil, matioliite occurs as a secondary hydrothermal mineral in the granite pegmatite. Some crystals are zoned to more iron-rich compositions with an Fe2+:Mg ratio of approximately 1:1, corresponding to an intermediate member of the burangaite-matioliite solid-solution series. Matioliite is intimately associated with fluorapatite, crandallite, and zoned gormanite-souzalite crystals. The matioliite forms prismatic to tabular, transparent, vitreous crystals up to 1 mm long (AM 91.1932-1936. Other associated minerals include quartz, muscovite, moraesite, childrenite, cassiterite and albite (Mindat).
Matioliite from the Gentil Claim - Image

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