Classification of Malachite |
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| IMA status: | Valid – first described prior to 1959 (pre-IMA) – “Grandfathered” |
|---|---|
| Strunz 8th edition ID: | 5/C.01-20 |
| Nickel-Strunz 10th (pending) edition ID: | 5.BA.10
5 : CARBONATES (NITRATES) |
| Dana 7th edition ID: | 16.3.2.1 |
| Dana 8th edition ID: | 16a.3.1.1
16a : ANHYDROUS CARBONATES CONTAINING HYDROXYL OR HALOGEN |
| Hey’s CIM Ref.: | 11.2.1
11 : Carbonates |
| mindat.org URL: | https://www.mindat.org/min-2550.html Please feel free to link to this page. |
Occurrences of Malachite |
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| Geological Setting: | It is the most common secondary mineral found in the oxidized zones of copper deposits. |
Physical Properties of Malachite |
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| Lustre: | Adamantine, Vitreous, Silky, Dull, Earthy |
| Diaphaneity (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 (Mohs): | 3½ – 4 |
| Hardness Data: | Measured |
| Tenacity: | Brittle |
| Cleavage: | Perfect Perfect on {201}, fair on {010}. |
| Fracture: | Irregular/Uneven, Sub-Conchoidal, Fibrous |
| Density (measured): | 3.6 – 4.05 g/cm3 |
| Density (calculated): | 4 g/cm3 |
Crystallography of Malachite |
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| Crystal System: | Monoclinic |
| Class (H-M): | 2/m – Prismatic |
| Cell Parameters: | a = 9.48Å, b = 12.03Å, c = 3.21Å β = 98° |
| Ratio: | a:b:c = 0.788 : 1 : 0.267 |
| Unit Cell Volume: | V 362.52 ų (Calculated from Unit Cell) |
| Z: | 4 |
| Morphology: | Crystals uncommon, usually short or long prismatic or acicular, parallel to [001]; often grouped in rosettes, sprays, or tufts. Botryoidal to mammilary 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]. |
