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Malachite
Chemical Formula	Cu2CO3(OH)2
Species	Carbonates
Crystal System	Monoclinic
Mohs Scale	3-4
Specific Gravity	3.6-4
Color	Bright green, dark green, blackish green, commonly banded in masses; green to yellowish green in transmitted light
Streak	light green
Luster	Adamantine, Vitreous, Silky, Dull, Earthy
Refractive Index	n = 1.655 n = 1.875 n = 1.909
Diaphaneity	Transparent, Translucent
Cleavage	PerfectPerfect on , fair on .
Fracture	Irregular/Uneven, Sub-Conchoidal, Fibrous
Crystal Habit：Massive, botryoidal, stalactitic, crystals are acicular to tabular prismatic
Geological Setting：It is the most common secondary mineral found in the oxidized zones of copper deposits.

Malachite is a copper carbonate hydroxide mineral, with the formula Cu₂CO₃(OH)₂. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and spaces, deep underground, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur. Typical malachite is laminated and whether or not microbes intervene in its formation is unknown.

Etymology and history

The stone's name derives (via Latin: molochītis, Middle French: melochite, and Middle English melochites) from Greek Μολοχ?τη? λ?θο? molochitis lithos, "mallow-green stone", from μολ?χη molōchē, variant of μαλ?χη malāchē, "mallow". The mineral was given this name due to its resemblance to the leaves of the Mallow plant.

Malachite was used as a mineral pigment in green paints from antiquity until about 1800. The pigment is moderately lightfast, very sensitive to acids and varying in color. The natural form was being replaced by its synthetic form, verditer amongst other synthetic greens. It is also used for decorative purposes, such as in the Malachite Room in the Hermitage, which features a huge malachite vase. "The Tazza", a large malachite vase, one of the largest pieces of malachite in North America and a gift from Tsar Nicholas II, stands as the focal point in the center of the room of Linda Hall Library.

Archeological evidence indicates that the mineral has been mined and smelted at Timna valley in Israel for over 3,000 years.

Occurrence

Malachite often results from weathering of copper ores and is often found together with azurite (Cu₃(CO₃)₂(OH)₂), goethite, and calcite. Except for its vibrant green color, the properties of malachite are similar to those of azurite and aggregates of the two minerals occur frequently. Malachite is more common than azurite and is typically associated with copper deposits around limestones, the source of the carbonate.

Large quantities of malachite have been mined in the Urals, Russia. It is found worldwide including in the Democratic Republic of Congo; Gabon; Zambia; Tsumeb, Namibia; Mexico; Broken Hill, New South Wales; Lyon, France; Timna valley, Israel, and in the Southwestern United States notably in Arizona.

Malachite gallery