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Formula: Ca3V4+5O9[Si2O5(OH)2][Si3O7(OH)2].11H2O
Polyoxovanadosilicate (with [(V4+,V5+)5O17] units),
vanadium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.24 measured
Hardness: 2
Colour: Dark olive green to black
Environments
Waipouaite is a new mineral, approved in 2020 and to date (September 2024) reported only from the
type locality.
Localities
At the type locality, the Aranga Quarry (Stone's Quarry; Hood Road Quarry), Aranga, Kaipara District, Northland
Region, New Zealand, waipouaite occurs in basalt as overgrowths
on thomsonite-Ca and
chabazite-Ca and as inclusions within
calcite and okenite. It forms dark
olive green to almost black prismatic crystals to 0.3 mm in length. Crystals are transparent to translucent with a
vitreous lustre.
Waipouaite is the first natural polyoxovanadosilicate and has a novel structure based on
[(V4+,V5+)5O17] polyoxovanadate units. Synthesis of
polyoxovanadosilicates has proved to be a great challenge, and the discovery of waipouaite demonstrates that
these compounds can form under natural conditions
(AM 109.5.934-939).
Waipouaite from the Aranga Quarry -
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