Copper Carbonate (unstable state) – Cu3(CO3)2(OH)2
Classification / Type:
The unstable state alters to malachite and is generally found in combination as azumalachite.
Colors / Varieties:
Violet blue commonly associated with malachite; azurite with large percentage of malachite is called azurmalachite. Transparency: Transparent (rare) to Opaque.
Crystal System / Forms:
Monoclinic System / Prismatic crystals, botryoidal, stalagmatic, massive, banded.
3.5 – 4
3.70 – 3.90
Cleavage / Fracture:
Perfect prismatic cleavage observed as schiller but not seen in aggregate / Conchoidal fracture.
Anisotropic, D.R.; Biaxial positive
Vitreous to waxy
Refractive Index / Birefringence:
1.730 – 1.840 / 0.110
Distinct shades of blue (in single crystal)
Cause of Color:
Specific Tests & Remarks:
Attacked by hydrochloric acid, light blue streak
Simulants (with key separation tests):
Azurmalachite (structure), Lapis Lazuli(structure, R.I., S.G.), Chrysocolla (structure, R.I., S.G.)
As a secondary mineral in copper deposits. Alters tomalachite and formed in association with malachite.
U.S.A. (Arizona), Namibia, France, Romania, Australia, Siberia.
Cuts & Uses:
Cabochons, beads, carvings.