General Information:
Chemical Formula:
Pb6As+++2O7Cl4
Composition:
(Molecular Weight = 1,646.85 gm)
Arsenic 9.10 % As
Lead 75.49 % Pb
Chlorine 8.61 % Cl
Oxygen 6.80 % O
Empirical Formula:
Pb6As2O7Cl4
Locality:
Langban and Harstig mines, Varmland, Sweden.
Name Origin:
Named from the Greek for "unusual", in reference to the composition.
Physical Properties:
Cleavage:
[001] Perfect
Color:
green yellow, yellow, or orange.
Density:
6.9 - 7.1, Average = 7
Diaphaniety:
Translucent
Habits:
Massive - Uniformly indistinguishable crystals forming large masses., Encrustations - Forms crust-like aggregates on matrix., Tabular - Form dimensions are thin in one direction.
Hardness:
2.5 - Finger Nail
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Greasy
Streak:
light yellow
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