General Information:
Chemical Formula:
KCdCu5(AsO4)4[As(OH)2O2]-2(H2O)
Composition:
(Molecular Weight = 1,201.88 gm)
Potassium 3.25 % K
Cadmium 9.35 % Cd
Copper 26.44 % Cu
Arsenic 31.17 % As
Hydrogen 0.50 % H
Oxygen 29.29 % O
Empirical Formula:
KCdCu5(AsO4)4(As(OH)2O2)·2(H2O)
Environment:
Single specimen found at the mine. Forms a series with calcioandyrobertsite.
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, specialist in documentation of new mineral species, in particular from low-temperature seco ndary parageneses.
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
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