Lavendulan

General Information:
 Chemical Formula:
NaCaCu5(AsO4)4Cl·5(H2O)
 Composition:
(Molecular Weight = 1,062.00 gm)
Sodium 2.16 % Na
Calcium 3.77 % Ca
Copper 29.92 % Cu
Arsenic 28.22 % As
Hydrogen 0.95 % H 
Chlorine 3.34 % Cl
Oxygen 31.64 % O 
 Empirical Formula:
NaCaCu5(AsO4)4Cl·5(H2O)
 Environment:
Secondary mineral in Cu-As deposits.
 Locality:
Jachimov, Bohemia, Czech Republic.
 Name Origin:
Named for the color (lavender blue).
Physical Properties:
 Cleavage:
[010] Perfect, [110] Indistinct
 Color:
blue, lavender blue, or greenish blue.
 Density:
3.54
 Diaphaniety:
Translucent
 Habits:
Botryoidal - "Grape-like" rounded forms (e.g.. malachite)., Encrustations - Forms crust-like aggregates on matrix.,
 Hardness:
2.5 - Finger Nail
 Luster:
Vitreous - Waxy
 Streak:
light blue
More details...