Annabergite
Image: Didier Descouens (CC BY-SA 3.0)
Mineral NameAnnabergite
Chemical FormulaNi₃(AsO₄)₂·8H₂O
Mohs Hardness2
Crystal Systemmonoclinic
Lustervitreous
Streak Colorpale green to greenish white
Cleavageperfect on {010}
Fractureuneven
Specific Gravity3.05
Colorsapple-green, yellowish-green, white
Transparencytransparent to translucent
Type LocalityKm-3 Mine, Lavrion Mines, Lavrion (Laurion; Laurium), Lavrion District Mines, Lavrion (Laurion; Laurium) District, Attikí (Attica; Attika) Prefecture, Greece
Mineral GroupPhosphates, Arsenates, Vanadates
Usescollector
Associated Mineralssiderite, nickel arsenides, erythrite
Rarityuncommon
Description
The image shows vibrant apple-green, acicular to bladed crystals of annabergite, often forming radiating aggregates, growing on a matrix of brownish-orange, blocky crystals, likely siderite.
Geological Context
Annabergite is a secondary mineral that forms in the oxidized zones of nickel-bearing arsenide ore deposits, resulting from the alteration of primary nickel arsenide minerals.
