Malachite

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Malachite
Malachite, Zaire.jpg
Malachite frae the Congo
General
Category Carbonate mineral
Formula
(repeating unit)
Cu2CO3(OH)2
Strunz classification 05.BA.10
Identification
Formula mass 221.1 g/mol
Color Bricht green, dark green, blackish green, commonly banded in masses; green tae yellaeish green in transmittit licht
Crystal habit Massive, botryoidal, stalactitic, crystals are acicular tae tabular prismatic
Crystal seestem Monoclinic—prismatic H-M Symbol (2/m) Space group P21/a
Twinnin Common as contact or penetration twins on {100} an {201}. Polysynthetic twinnin an aa present.
Cleavage Perfect on {201} fair on {010}
Fractur Subconchoidal tae uneven
Mohs scale hairdness 3.5–4.0
Luster Adamantine tae vitreous; silky if fibrous; dull tae yirdy if massive
Streak licht green
Diaphaneity Translucent tae opaque
Specific gravity 3.6–4
Optical properties Biaxial (–)
Refractive index nα = 1.655 nβ = 1.875 nγ = 1.909
Birefringence δ = 0.254
References [1][2][3]

Malachite is a copper carbonate hydroxide mineral, wi the formula Cu2CO3(OH)2. This opaque, green bandit mineral crystallizes in the monoclinic crystal seestem, an maist eften furms botryoidal, fibrous, or stalagmitic masses, in fracturs an spaces, deep unnergrund, whaur the watter table an hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare but dae occur as slender tae acicular prisms. Pseudomorphs efter mair tabular or blocky azurite crystals an aa occur.[3] Typical malachite is laminatit an whether or nae microbes intervene in its furmation is unkent.

References[eedit | eedit soorce]