16 Photos
Annabergite
Chemical Formula	Ni3(AsO4)2·8H2O
Species	Phosphates
Crystal System	Monoclinic
Mohs Scale	1-2
Specific Gravity	3.07
Color	Apple-green, pale green, pale rose or pale pink, white, gray; may be zoned
Streak	Pale green to white
Luster	Sub-Adamantine, Sub-Vitreous, Pearly, Earthy
Refractive Index	n = 1.622 n = 1.658 n = 1.687
Diaphaneity	Transparent, Translucent
Cleavage	PerfectPerfect on , indistinct on , .
Crystal Habit：Usually as fibrous veinlets, crystalline crusts, or earthy; rare as well formed crystals
Geological Setting：An uncommon oxidation zone mineral in Ni-Co-As deposits, frequently post-mine on ores exposed to the atmosphere.

Annabergite is an arsenate mineral consisting of a hydrous nickel arsenate, Ni₃(AsO₄)₂·8H₂O, crystallizing in the monoclinic system and isomorphous with vivianite and erythrite. Crystals are minute and capillary and rarely met with, the mineral occurring usually as soft earthy masses and encrustations. A fine apple-green colour is its characteristic feature. It was long known (since 1758) under the name nickel ochre; the name annabergite was proposed by H. J. Brooke and W H. Miller in 1852, from Annaberg in Saxony, one of the localities of the mineral. It occurs with ores of nickel, of which it is a product of alteration. A variety, from Creetown in Kirkcudbrightshire, in which a portion of the nickel is replaced by calcium, has been called dudgeonite, after P. Dudgeon, who found it.

Closely related is cabrerite wherein some of the nickel is replaced by magnesium. It is named for Sierra Cabrera in Spain where it was originally found.