Mineral Information and Data:

Annabergite
Ni3(AsO4)2 • 8H2O [CNMNC approved formula]

Named after its locality: Annaberg, Germany.

IMA status : Valid species (Pre-IMA 1852) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
40.03.06.04  
  (40) Hydrated Phosphates
  (40.03) where (A++)3 (XO4)2 · x(H2O)
  (40.03.06) Vivianite Group
  
Nickel-Strunz
(10th edition) :
08.CE.40
  (08) Phosphates, Arsenates, Vanadates
  (08.C) Phosphates without Additional Anions, with H2O
  (08.CE) With only medium-sized cations, RO4:H2O about 1:2.5
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 10.179 Å, b = 13.309 Å, c = 4.725 Å, b = 105°
Crystal Habit: Crystals prismatic, flattened; striated; usually crystalline crusts, earthy masses
  
Color: Apple green, gray, pale green to intense yellow-green, white, may be zoned
Diaphaneity: Transparent to translucent
Luster: Adamantine, pearly on cleavage, may be dull, earthy
Hardness (Mohs): 1.5 - 2.5
Measured Density: 3.07 g/cm3
Cleavage: 3; {010} perfect, {100} and {102} indistinct
Tenacity: Flexible in thin laminae, sectile
Streak: Pale green to white
  
Polymorphism and Series: Forms a series with erythrite
Geologic Setting: An uncommon secondary mineral, formed by the alteration of Co–Ni-bearing arsenides and sulfides, in the oxidized zone of hydrothermal mineral deposits.
Mineral Association: Erythrite, retgersite, gersdorffite, nickeline, maucherite, nickel-skutterudite
  
Synonyms/varieties: Cabrerite (Mg containing variety)

 

Annabergite
Origin: Laurium, Greece
Sample size: Microscopic image
Photo and Owner: Lou Perloff

 

Annabergite
Origin: Km 3 adit, Agios Constantinos, Greece
Sample size: 5.2 x 3.6 x 2.8 cm
Photo: Dan Weinrich

 

Annabergite
(zoom-in of above)

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