Malachite

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Malachite
Malachite, Zaire.jpg
Malachite frae the Congo
General
CategoryCarbonate mineral
Formula
(repeatin unit)
Cu2CO3(OH)2
Strunz clessification05.BA.10
Creestal seestemMonoclinic—prismatic H-M Symbol (2/m) Space group P21/a
Identification
Formula mass221.1 g/mol
ColourBricht green, dark green, blackish green, commonly banded in masses; green tae yellaeish green in transmittit licht
Creestal habitMassive, botryoidal, stalactitic, crystals are acicular tae tabular prismatic
TwinninCommon as contact or penetration twins on {100} an {201}. Polysynthetic twinnin an aa present.
CleavagePerfect on {201} fair on {010}
FracturSubconchoidal tae uneven
Mohs scale haurdness3.5–4.0
SkinkleAdamantine tae vitreous; silky if fibrous; dull tae yirdy if massive
Streaklicht green
DiaphaneityTranslucent tae opaque
Speceefic gravity3.6–4
Optical propertiesBiaxial (–)
Refractive indexnα = 1.655 nβ = 1.875 nγ = 1.909
Birefringenceδ = 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]