Paravauxite

paravauxite

wavellite

crandallite

sigloite

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Formula: Fe2+Al2(PO4)2(OH)2.8H2O
Hydrated phosphate containing hydroxyl, laueite group, triclinic paramorph of monoclinic metavauxite
Specific gravity: 2.36
Hardness: 3
Streak: White
Colour: Colourless to pale greenish white
Environments

Pegmatites
Hydrothermal environments

Paravauxite is a rare mineral in hydrothermal tin veins and in complex granitic pegmatites (Mindat). Associated minerals include vauxite, metavauxite and wavellite (Webmin).

Localities

At the type locality, the Siglo Veinte mine, Llallagua, Rafael Bustillo, Potosí, Bolivia, paravauxite occurs as a later secondary phosphate in hydrothermal tin veins. It almost always occurs as individual crystals to 2 cm perched on wavellite encrusting quartz in the tin veins and porphyry breccia fragments; childrenite has often been observed in association with the paravauxite on wavellite, and paravauxite crystals have been found in vugs in wavellite. It has been found on crusts of vauxite and as crystals perched on metavauxite needles. Other associated minerals include allophane, sigloite, quartz and crandallite (Min Rec 37.2.145, Mindat). Sigloite forms oxidation pseudomorphs after paravauxite (AM 47.1 to 8).

At the Chickering Mine, Walpole, Cheshire county, New Hampshire, USA, paravauxite-laueite-group minerals occur as sprays and clusters of thin bladed crystals (R&M 90.5.420).

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