Annabergite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameAnnabergite
Chemical FormulaNi3(AsO4)2·8H2O
Mohs Hardness1.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorpale green to greenish white
Cleavageperfect on {100}
Fractureuneven
Specific Gravity3.07
Colorsapple green, emerald green, yellowish green, white
Transparencytransparent
Type LocalityLavrion (Laurion; Laurium), Lavrion District Mines, Lavrion (Laurion; Laurium) District, Attikí (Attica; Attika) Prefecture, Greece
Mineral GroupArsenates
Usescollector
Associated Mineralserythrite, nickel-bearing minerals, arsenopyrite
Rarityuncommon
Description
Annabergite typically forms as crusts, coatings, or radiating aggregates of small, often acicular or tabular crystals, exhibiting a distinctive apple-green to emerald-green color. The specimen shows a vibrant green coating on a matrix.
Geological Context
Annabergite is a secondary mineral formed in the oxidized zones of nickel-bearing ore deposits, often as an alteration product of nickel arsenides. It is commonly found in association with other secondary arsenates.
