General Information:
Chemical Formula:
KCaCu5(AsO4)4[As(OH)2O2]-2(H2O)
Composition:
(Molecular Weight = 1,129.55 gm)
Potassium 3.46 % K
Calcium 3.55 % Ca
Copper 28.13 % Cu
Arsenic 33.16 % As
Hydrogen 0.54 % H
Oxygen 31.16 % O
Empirical Formula:
KCaCu5(AsO4)4(As(OH)2O2)·2(H2O)
Environment:
Single specimen found at the mine. Forms a series with andyrobertsite.
IMA Status:
Approved IMA (Dana # Added)
Locality:
Tsumeb Mine, Tsumeb, Namibia.
Name Origin:
Named after Andrew C. Roberts (1950-), mineralogist with the Geological Survey of Canada.
Physical Properties:
Cleavage:
[100] Good
Color:
electric blue.
Density:
4.011
Diaphaniety:
Transparent
Habits:
Platy - Sheet forms (e.g. micas)., ,
Hardness:
3 - Calcite
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
pale blue
More details...