Mineral - Annabergite
Annabergite
Chemical Properties
Mineral Class
Arsenates
Toxicity
low
Formula
Ni₃(AsO₄)₂ · 8H₂O
Unit Cell
a=10.18 b=13.31 c=4.73 β=105° Z=2
Physical Properties
Hardness
1.5 - 2.5
Streak
whitegreen
Density
Normal (2-3,5)
Cleavage
Perfect after {010}, indistinct after {100} and {102}
Fracture
splintery,
uneven
Tenacity
Elastic-flexible
Optical Properties
Color
green
Birefringence
0.065
Luster
Adamantine,
Pearly
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/m (12)
Habit
acicular, platelet-shaped, prismatic, tabular
Formation
Secondary, in the oxidation zone of nickel deposits, from primary Co-Ni-containing sulphides and arsenates
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Annabergite
Composition
Elements
Mass
As₂O₅
37.25
SiO₂
0.41
FeO
0.56
CoO
3.40
NiO
33.82
MgO
0.21
H₂O
24.83
Canada (Palache et al. 1952)
Groups and Members
Vivianite-Group
Name and first discovery : Named after the district town of Annaberg-Buchholz, the mineral's type locality. First described in 1852.
Chemistry :
Synonyms : Cordillerite, nickel green, nickel ochre, nickel blossom
Varieties :
Abbreviation : Anb
literature
Palache, C., Berman, H., & Frondel, C. (1952). Dana's system of mineralogy. Geologiska Föreningen i Stockholm Förhandlingar , 74 (2), 218-219.