While azurite is not an extremely abundant mineral and is rarely found in large deposits, it has been used in a number of ways. Some of these are explained below.
Copper Prospecting and Mining
Geologists know that abundant azurite is often found in the rocks above deposits of copper ore. That enables them to use azurite as an indicator mineral in the search for subsurface copper deposits. The presence of abundant azurite indicates the possibility of finding some form of copper ore below, nearby, or up a contemporary or ancient hydraulic gradient.
Azurite has been used as an ore of copper metal for thousands of years. The ancient Egyptians mined it on the Sinai Peninsula and smelted it to produce copper. Today, azurite deposits on their own are usually not large enough to be worth opening a copper mine. Where other copper ores are mined, azurite might be removed if it is of adequate grade and easy to mine.
Jewelry and Ornamental Stone
Azurite is easy to cut and shape into cabochons, beads, small carvings, and ornaments. It also accepts a bright polish. Unfortunately, azurite has problems that limit its use in jewelry. The greatest concern is the fact that azurite has a Mohs hardness of just 3.5 to 4.0. It also is brittle and can break along cleavage planes. This lack of durability makes it easily damaged if used in a ring, bracelet, or other jewelry item that is subject to abrasion.
Azurite also slowly weathers to malachite. This results in a lightening and greening of the gemstone’s deep blue color. Store azurite jewelry in darkness, away from heat, and where air circulation is limited. This might be in a closed jewelry box or drawer.
Azurite jewelry is difficult to clean. A gentle cleaning with a soft damp cloth or with cool soapy water is best. Abrasive cleaners or excessive cleaning will damage the stone. Ultrasonic and steam cleaning can cause damage.
If jewelry containing azurite needs repairs, the repairs should be done in a way that does not heat the stone. Hydroxide minerals are very sensitive to heat. Heating will cause azurite to green or blacken.
Azurite is rarely treated to enhance its color. However, it is frequently treated with resins and other substances that impregnate and stabilize the rough. Much of the inexpensive material sold as “azurite” is a composite made of crushed azurite in a binder of resin or other substance. Often, chrysocolla, malachite, or other minerals are blended in.
An interesting ornamental stone found near the border between China and Pakistan has recently appeared in the lapidary market. It is a white granite with orbs of bright blue azurite dispersed through the stone. Most people who see it initially think that it is fake, but it can be sawn to reveal round azurite areas inside, and x-ray diffraction reveals azurite. This azurite granite is commonly called “K2 granite” after the second-highest mountain in the world, because the rock was first discovered near the base of the mountain.
| 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. |