Chemical composition -- A hydrated copper carbonate.
Color -- Azure blue.
Optics -- R.I 1.73-1.84. Biaxial positive.
Durability -- Hardness 3.5-4.
Crystal structure -- Monoclinic (usually massive).
Specific Gravity --3.77.
Sources -- Copper mines throughout the world, notably southwestern U.S., Australia, Mexico, Namibia.
Facetable crystals are small and rare, but azurite is frequently found in massive deposits in combination with malachite , with which it makes an interesting color combination for cabochons and ornamental items.