Malachite

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Malachite
Malachite, Zaire.jpg
Malachite frae the Congo
General
Category Carbonate mineral
Formula
(repeatin unit)
Cu2CO3(OH)2
Strunz clessification 05.BA.10
Creestal seestem Monoclinic—prismatic H-M Symbol (2/m) Space group P21/a
Identification
Formula mass 221.1 g/mol
Colour Bricht green, dark green, blackish green, commonly banded in masses; green tae yellaeish green in transmittit licht
Creestal habit Massive, botryoidal, stalactitic, crystals are acicular tae tabular prismatic
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 haurdness 3.5–4.0
Skinkle Adamantine tae vitreous; silky if fibrous; dull tae yirdy if massive
Streak licht green
Diaphaneity Translucent tae opaque
Speceefic 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] teepical malachite is laminatit an whether or nae microbes intervene in its furmation is unkent.

References[eedit | eedit soorce]