Azurite and Malachite

Azurite
Copper Carbonate Hydroxide, Cu3(CO3)2-(OH)2
Crystal System: Monoclinic
Hardness: 3.5-4.0
Density: 3.83

Azurite occurs as a secondary mineral in the oxidized zones of copper deposits. It is associated with malachite, chrysocolla, cuprite, native copper, chalcocite, calcite, and limonite. Azurite forms at a lower temperature than malachite, which it commonly replaces as a pseudomorph. Pseudomorphs of azurite after other minerals are also common. Azurite also occurs in sandstones where carbolic waters mixed with waters rich in copper sulfates.

Azurite occurs as elongated or tabular prismatic crystals exhibiting various shades of transparent to translucent azure blue with a vitreous luster. Crystals are often intergrown or grouped in radiating aggregates and also occur as granular or concretionary masses. Azurite often forms sharp crystals in contrast to malachite.

Malachite
Copper Carbonate Hydroxide, Cu2CO3(OH)2
Crystal System: Monoclinic
Hardness: 3.5-4.0
Density: 4.0

Malachite occurs as an alteration product in the oxidized zones of copper deposits. It is associated with azurite, calcite, chrysocolla, cuprite, tenorite and limonite. Pseudomorphs of malachite after azurite are common. Malachite also occurs in sandstones as disseminations deposited by meteoric waters.

Malachite sometimes occurs as acicular crystals in fibrous, radiating masses. It commonly occurs as a green coating on other copper minerals and as emerald-green botryoidal masses with concretionary, banded structures.

Stuart provides the following remarks:

"Azurite and malachite are like chocolate and peanut butter, they are always great together. This one is from the Morenci Mine, Morenci, Arizona. Brilliant deep blue bladed azurite crystals blending with rich forest green velvety malachite is one of the all time great mineral combinations."


Rocks from Stuart Wilensky's Collection

Index of Specimen Images

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bkeller@rockhounds.com 8/5/95