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16.21: Azurite

  • Page ID
    4357
  • Azurite
    Chemical composition Cu3(CO3)2(OH)2
    Crystal system Monoclinic
    Habit Short columlar, botryoidal
    Cleavage Indistinct
    Fracture Conchoidal, uneven, brittle
    Hardness 3 1/2 - 4
    Optic nature Biaxial +
    Refractive index 1.720-1.848
    Birefringence 0.108-0.110
    Specific gravity 3.7-3.9
    Lustre Vitreous
    Pleochroism Light blue, dark blue

    File:Azurite.jpg

    Figure \(\PageIndex{1}\): Botryoidal Azurite
    Bisbee, Arizona

    Azurite forms directly from the oxidation of copper ore. Azurite (blue) and malachite (green) are often found together because azurite tends to alter into malachite. Because of azurite's intense blue color, it was once used as a pigment for oil paints. Unfortunately, time has caused those originally blue skies and bodies of water to go decidedly green. In ancient Egypt, azurite paint was used by temple priests to paint and decorate the Third Eye on their foreheads believing that it increased their powers. The ancient Chinese revered azurite as the Stone of Heaven, able to open spiritual doorways.

    Localities

    • dark blue almost black crystals have come from Tsumbed (Namibia) and Morocco
    • Australia (Queensland), Chile, Mexico, Russia (Ural) and United States (Arizona, New Mexico)

    Sources

    • Gemstones of the world - Walter Schumann