Mineral - Agardite-(Ce)
Agardite-(Ce)
Chemical Properties
Mineral Class
Arsenates
Toxicity
low
Formula
CeCu₆(AsO₄)₃(OH)₆ · 3H₂O
Unit Cell
a=13.60 c=5.95 Z=2
Physical Properties
Hardness
3
Streak
whitegreen white
Density
Heavy (3,5-6)
Cleavage
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
green
Birefringence
0.085
Luster
Vitreous,
Silky,
Resinous
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
hexagonal
Point Group
hexagonal-dipyramidal - 6/m
Space Group
P6 3 /m (176)
Habit
tufty, spherical, acicular, prismatic, radial
Formation
Formed as a secondary mineral in the oxidation zone of copper-bearing sulfide deposits through crystallization from rare-earth- and arsenate-bearing solutions under supergene conditions
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Agardite-(Ce), Agardite, Chlorotile-(Ce)
Composition
Elements
Mass
CaO
1.21
CuO
42.91
Fe₂O₃
0.39
Y₂O₃
0.91
La₂O₃
2.32
Ce₂O₃
4.99
Nd₂O₃
2.38
Sm₂O₃
0.56
Eu₂O₃
0.26
Gd₂O₃
0.52
Dy₂O₃
0.18
SiO₂
0.96
As₂O₅
30.91
SO₃
0.40
H₂O
11.10
Germany (Walenta & Theye 2004)
Groups and Members
Mixite-Group
Name and first discovery : Named after the French geologist Jules Agard (1916-2003). First discovered in 2003
Chemistry :
Synonyms : Chlorotile-(Ce)
Varieties :
Abbreviation : Agr-Ce
literature
Walenta, K. and T. Theye (2004) Agardite-(Ce) of the Clara mine in the central Black Forest. Enlightenment, 55, 17-23