Azurite is an azure-blue copper mineral, occasionally found as prismatic crystals (rarely faceted), but more usually in massive form intergrown with malachite.

Found specifically in copper-mining areas for example Australia, Chile, Russia, Africa, and China. Stones from Chessy, near Lyons in France are known as chessylite.

Chemical Composition: 

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.

Hardness: 

3.5 - 4

Specific Gravity: 

3.70 - 3.90

Cleavage / Fracture: 

Perfect prismatic cleavage observed as schiller but not seen in aggregate / Conchoidal fracture.

Optic Character: 

Anisotropic, D.R.; Biaxial positive

Lustre: 

Vitreous to waxy

Refractive Index / Birefringence: 

1.730 - 1.840 / 0.110

Pleochroism: 

Distinct shades of blue (in single crystal)

Magnification: 

Surface texture

U.V. Fluorescence: 

Inert

Spectrum: 

Not characteristic

Cause of Color: 

Copper

Specific Tests: 

Attacked by hydrochloric acid, light blue streak.

Simulants (with separation tests): 

Azurmalachite (structure), Lapis Lazuli (structure, R.I., S.G.), Chrysocolla (structure, R.I., S.G.)

Geological Occurrence: 

As a secondary mineral in copper deposits. Alters to malachite and formed in association with malachite.

Sources: 

U.S.A. (Arizona), Namibia, France, Romania, Australia, Siberia.

Cuts & Uses: 

Cabochons, beads, carvings.