Mineral - Bartelkeite
Bartelkeite
Chemical Properties
Mineral Class
Oxides and Hydrxides
Toxicity
none
Formula
Pb(Fe²⁺Ge)[Ge₂O₇](OH)₂ · H₂O
Unit Cell
a=5.83 b=13.61 c=6.31β=127° Z=2
Physical Properties
Hardness
4
Streak
white
Density
Heavy (3,5-6)
Cleavage
Distinct after {101}
Fracture
Tenacity
Optical Properties
Color
browngreenyellow browngreen yellow
Birefringence
0.028
Luster
Adamantine
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
P2 1 /m (11)
Habit
sheaf-shaped, crusty, acicular, prismatic
Formation
In the oxidation zone of polymetallic germanium-bearing deposits
Paragenesis
Twinning
Rarity
Rare
Synonyms
Bartelkeite
Composition
Elements
Mass
PbO
34.10
FeO
10.60
GeO₂
46.20
As₂O₅
2.80
SiO₂
0.10
ZnO
0.08
P₂O₅
0.04
Cl
0.20
SO₃
0.14
H₂O
5.64
Namibia (Keller et al. 1981)
Name and first discovery: Named after the German mineralogist Wolfgang Bartelke (1940). First described in 1979.
Chemism:
Synonyms:
Varieties:
Abbreviation: Btk
Literature
Keller, P., Hess, H., & PJ, D. (1981). BARTELKEIT, PBFE2+ GE3C8, A NEW GERMANIUM MINERAL FROM TSUMEB, NAMIBIA.