Formula: Mn2+3(AsO4)2.3H2O
Hydrated normal arsenate, ludlamite group, manganese-bearing mineral
Specific gravity: 2.94 measured, 3.48 calculated
Hardness: 3
Streak: Whte
Colour: White, pale pinkish white, also very pale pink
Luminescence: Does not fluoresce in UV and there is no phosphorescen#

Metamorphic environments


At the type locality, the Sterling mine, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex County, New Jersey, USA, one specimen of sterlinghillite has been reported from the 340'level, on seams in the franklinite-sphalerite ore which is in contact with a probable seam of löllingite and calcite. Sterlinghillite, that appears to be the last mineral to form, occurs in two habits on the type specimen; both habits are on seam surfaces. In one of these habits, sterlinghillite occurs as rather sparse bundles of very soft pearly crystals. The second habit is that of tiny hemispherical clusters of platy crystals that appear to be randomly intergrown. It may have formed from the decomposition of löllingite (AM 66.182-184).
The ore body is a metamorphosed stratiform zinc orebody, and minerals associated with sterlinghillite include franklinite, sphalerite, löllingite and calcite (HOM).

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