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Formula: Ca2Mn2+3(AsO4)2(OH)4.9H2O
Hydrated arsenate with hydroxyl
Crystal System: Hexagonal
Specific gravity: 2.85 measured, 2.90 calculated
Hardness: 3
Streak: Pale orange
Colour: Dark red to nearly black
Environments
Wallkilldellite is an extremely rare arsenate.
Localities
The type locality is the Sterling mine, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex county, New Jersey, USA. Here
wallkilldellite is found only rarely in massive granular franklinite -
willemite ore from a metamorphosed stratiform zinc orebody,
associated with manganoan cuprian
adamite, franklinite,
willemite and calcite
(HOM).
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