Apachite - Encyclopedia

Class : Silicates
Subclass : Cyclosilicates
Crystal System : Monoclinic
Chemistry : Cu₉Si₁₀O₂₉ 11H₂O
Rarity : Very rare

Apachite is an extremely rare hydrated copper silicate which forms small fibroradiated spherolites composed of tiny crystals of a magnificent sky blue. It owes its name to the Apache Indians, inhabitants of the discovery region : the Christmas Mine (Arizona). It is a metamorphic mineral found in tactites (calcium hornfels) replacing an assembly of garnet, diopside, calcite and sulphides.

Main photo : Apachite and calcite from the Christmas Mine, Arizona, USA - © Stephan Wolfsried

Apachite in the World

Apachite is found in small spherolites at the Christmas Mine (Arizona) its type locality, and in crusts and encrustations at Alforja Mine (Spain), Kandesei (Namibia) and in the Agardag Massif (Russia).

Right photo : Apachite from the Christmas Mine, Arizona, USA - © Stephan Wolfsried

Apachite in France

Apachite is not reported in the French subsoil.

Twinning

No known twins for this mineral species.

Fakes and treatments

No fake identified for this mineral species, but sometimes confused with fibrous dioptase.

Hardness : 2
Density : 2.80
Fracture : Conchoidal to irregular
Trace : Pale blue

TP : Translucent to transparent
RI : 1.610 to 1.650
Birefringence : 0.040
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : -

Magnetism : None
Radioactivity : None