Manganoarrojadite-(KNa)

manganoarrojadite-(KNa)

vivianite

goyazite

arrojadite

Images

Formula: KNa₅MnFe₁₃Al(PO₄)₁₁(PO₃OH)(OH)₂
Phosphate, arrojadite group, manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.53 calculated
Hardness: 4½
Streak: Pale green
Colour: Olive green
Environments

Pegmatites

Manganoarrojadite-(KNa) is a new mineral, approved in 2020 and to date (May 2022) reported only from the type locality.

Localities

At the type locality, the Palermo No. 1 Mine, Groton, Grafton county, New Hampshire, USA, manganoarrojadite-(KNa) was found in a phosphate-bearing granite pegmatite. It forms olive green anhedral grains up to 1 × 1.5 cm in size combined in aggregates with vivianite, goyazite, quartz and calcite. Manganoarrojadite-(KNa) is the first arrojadite-group mineral with manganese dominant on the site usually occupied by calcium and without calcium as the dominant cation at any cation site (MM 84.6.932-940).

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