Mineral Type - Malachite
Malachite is a green, very common secondary copper mineral with a widely variable habit. Typically it is found as crystalline aggregates or crusts, often banded in appearance, like agates. It is also often found as botryoidal clusters of radiating crystals, and as mammillary aggregates as well. Single crystals and clusters of distinguishable crystals are uncommon, but when found they are typically acicular to prismatic. It is also frequently found as a pseudomorph after Azurite crystals, which are generally more tabular in shape.
Transparency: Transparent, Translucent
Colour: Bright green, with crystals deeper shades of green, even vary dark to nearly black; green to yellowish green in transmitted light
Streak: Light green
Hardness: 3½ - 4 on Mohs scale. Measured
Tenacity: Brittle
Cleavage: Perfect. Perfect on {201}, fair on {010}
Fracture: Irregular/Uneven, Sub-Conchoidal, Fibrous
Density: 3.6 - 4.05 g/cm3 (Measured) 4 g/cm3 (Calculated)
Elements listed: C, Cu, H, O
Common Impurities: Zn,Co,Ni
Class (H–M): 3 2 – 2/m - Prismatic
Space Group: P21/b
Morphology: Crystals uncommon, usually short or long prismatic or acicular, parallel to [001]; often grouped in rosettes, sprays, or tufts. Botryoidal to mammillary aggregates of radiating fibrous crystals more common. It may also be massive, compact, and stalactic.
Twinning: Untwinned crystals are extremely rare. Typically twinned on {100}, sometimes as penetration or polysynthetic twinning with the axis parallel to [201].
Name
Named in antiquity (see Pliny the Elder, 79 CE) molochitus after the Greek μαλαχή, "mallows," in allusion to the green color of the leaves. Known in the new spelling, malachites, at least by 1661.Physical Properties
Lustre: Adamantine, Vitreous, Silky, Dull, EarthyTransparency: Transparent, Translucent
Colour: Bright green, with crystals deeper shades of green, even vary dark to nearly black; green to yellowish green in transmitted light
Streak: Light green
Hardness: 3½ - 4 on Mohs scale. Measured
Tenacity: Brittle
Cleavage: Perfect. Perfect on {201}, fair on {010}
Fracture: Irregular/Uneven, Sub-Conchoidal, Fibrous
Density: 3.6 - 4.05 g/cm3 (Measured) 4 g/cm3 (Calculated)
Chemical Properties
Formula: Cu2(CO3)(OH)2Elements listed: C, Cu, H, O
Common Impurities: Zn,Co,Ni
Crystallography
Crystal System: MonoclinicClass (H–M): 3 2 – 2/m - Prismatic
Space Group: P21/b
Morphology: Crystals uncommon, usually short or long prismatic or acicular, parallel to [001]; often grouped in rosettes, sprays, or tufts. Botryoidal to mammillary aggregates of radiating fibrous crystals more common. It may also be massive, compact, and stalactic.
Twinning: Untwinned crystals are extremely rare. Typically twinned on {100}, sometimes as penetration or polysynthetic twinning with the axis parallel to [201].
