The most diagnostic property of azurite is it distinctive deep blue color. It is also soft with a Mohs hardness of only 3.5 to 4. It contains copper, which gives its blue color and a specific gravity of 3.7 to 3.9, which is exceptionally high for a non-metallic mineral. Azurite is a carbonate mineral and produces a slight effervescence with dilute hydrochloric acid, producing a light blue liquid. Azurite produces a light blue streak on unglazed porcelain.
| Physical Properties of Azurite | |
| Chemical Classification | Carbonate |
| Color | Deep blue to violet blue; “azure” |
| Streak | Light blue |
| Luster | Vitreous, earthy |
| Diaphaneity | Opaque, translucent, transparent |
| Cleavage | Two distinct directions, one perfect, one poor |
| Mohs Hardness | 3.5 to 4 |
| Specific Gravity | 3.7 to 3.9 |
| Diagnostic Properties | Deep blue color, effervescence in dilute HCl, high specific gravity, low hardness. |
| Chemical Composition | Copper carbonate. Cu3(CO3)2(OH)2 |
| Crystal System | Monoclinic |
| Uses | Minor ore of copper, gem material, ornamental stone, pigment. |