Malachite


Malachite
Malachite

Malachite from the Congo
General
Category Carbonate mineral
Chemical formula Cu2CO3(OH)2
Strunz classification 05.BA.10
Identification
Molar mass 221.1 g/mol
Color Bright green, dark green, blackish green, commonly banded in masses; green to yellowish green in transmitted light
Crystal habit Massive, botryoidal, stalactitic, crystals are acicular to tabular prismatic
Crystal system Monoclinic—prismatic H-M Symbol (2/m) Space group P21/a
Twinning Common as contact or penetration twins on {100} and {201}. Polysynthetic twinning also present.
Cleavage Perfect on {201} fair on {010}
Fracture Subconchoidal to uneven
Mohs scale hardness 3.5–4.0
Luster Adamantine to vitreous; silky if fibrous; dull to earthy if massive
Streak light green
Diaphaneity Translucent to 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 mineral, with the formula Cu2CO3(OH)2. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur.[3]

Contents

Etymology and history

The stone's name derives (via Latin: molochītis, Middle French: melochite, and Middle English melochites) from Greek Μολοχίτης λίθος molochitis lithos, "mallow-green stone", from μολόχη molōchē, variant of μαλάχη malāchē, "mallow".[4] The mineral was given this name due to its resemblance to the leaves of the Mallow plant.[5]. In turn, the stone's Greek name may be borrowed from the Hebrew word: מלך Melekh (with root letters: M-L-KH) which means: king-since the stone was considered royal and was used by royalty and Arabic (ملك Malak or Malek". Hence, this stone's Hebrew name is; מלכי Malakhi and, in Arabic: الملكيت (al) Malkit-(the) Malchite (stone).

Malachite was used as a mineral pigment in green paints from antiquity until about 1800. The pigment is moderately lightfast, very sensitive to acids and varying in color. The natural form was being replaced by its synthetic form, verditer amongst other synthetic greens. It is also used for decorative purposes, such as in the Malachite Room in the Hermitage, which features a large malachite vase. "The Tazza", one of the largest pieces of malachite in North America and a gift from Tsar Nicholas II, stands as the focal point in the center of the room of Linda Hall Library.

Occurrence and historical uses

Malachite often results from weathering of copper ores and is often found together with azurite (Cu3(CO3)2(OH)2), goethite, and calcite. Except for its vibrant green color, the properties of malachite are similar to those of azurite and aggregates of the two minerals occur frequently. Malachite is more common than azurite and is typically associated with copper deposits around limestones, the source of the carbonate.

Large quantities of malachite have been mined in the Urals, Russia. It is found worldwide including in the Democratic Republic of Congo; Gabon; Zambia; Tsumeb, Namibia; Mexico; Broken Hill, New South Wales; Lyon, France; and in the Southwestern United States notably in Arizona.[6]

In Israel, malachite is extensively mined at Timna valley, often called King Solomon's Mines, although research has revealed an interruption in mining activity at the site during the 10th century BC, the time of the biblical Solomon.[7] Archeological evidence indicates that the mineral has been mined and smelted at the site for over 3,000 years. Most of Timna's current production is also smelted, but the finest pieces are worked into silver jewelry.

Malachite gallery

See also

References

  1. ^ Malachite in Handbook of Mineralogy
  2. ^ Malachite at Webmineral
  3. ^ a b Malachite at Mindat
  4. ^ Malachite, Dictionary.com
  5. ^ Harper, Douglas. "malachite". Online Etymology Dictionary. http://www.etymonline.com/index.php?term=malachite. 
  6. ^ Mindat map with over 8500 locations
  7. ^ Parr, Peter J review of "Timma: Valley of the Biblical Copper Mines" by Beno Rothenberg Bulletin of the School of Oriental and African Studies, University of London, Vol. 37, No. 1, In Memory of W. H. Whiteley (1974), pp. 223–224

Further reading


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Look at other dictionaries:

  • malachite — [ malaʃit; malakit ] n. f. • 1685; melochite XIIe; lat. molochitis, mot gr., de molokhê ou malakhê « mauve » ♦ Carbonate de cuivre naturel, pierre d un beau vert diapré utilisée dans la fabrication d objets d art. Écritoire en malachite. ●… …   Encyclopédie Universelle

  • Malachite — Mal a*chite, n. [Fr. Gr. mala chh a mallow, from its resembling the green color of the leaf of mallows: cf. F. malachite. Cf. {Mallow}.] (Min.) Native hydrous carbonate of copper, usually occurring in green mammillary masses with concentric… …   The Collaborative International Dictionary of English

  • malachite — [mal′ə kīt΄] n. [ME melochites < L molochites < Gr molochitēs, a stone (? malachite) < malachē, molochē, mallow (its color is like that of mallow leaves): < ? Heb malluaḥ, a lettuce like plant > L malva,MALLOW] a bright green,… …   English World dictionary

  • malachite — common green ore of copper, late 14c., from French, ultimately from Gk. malachitis (lithos) mallow (stone), from malakhe mallow (see MALLOW (Cf. mallow) (n.)); the mineral traditionally so called from resemblance of its color to that of the… …   Etymology dictionary

  • malachite — ► NOUN ▪ a bright green copper containing mineral. ORIGIN Old French melochite, from Greek malakh mallow …   English terms dictionary

  • Malachite — Pour les articles homonymes, voir Malachite (homonymie). Malachite Catégorie V : carbonates et nitrates[1] …   Wikipédia en Français

  • malachite — /mal euh kuyt /, n. 1. a green mineral, basic copper carbonate, Cu2CO3(OH)2, an ore of copper, used for making ornamental articles. 2. a ceramic ware made in imitation of this. [1350 1400; < Gk malách(e) MALLOW + ITE1; r. ME melochites < MF… …   Universalium

  • MALACHITE — s. f. (On prononce Malakite .) Pierre opaque, mamelonnée et d un beau vert, qui est susceptible de poli. La malachite est un minerai de cuivre …   Dictionnaire de l'Academie Francaise, 7eme edition (1835)

  • malachite —    A green mineral used in jewelry, intarsia, and as a pigment. Illustrated are some polished pieces, mared by malachite s typical multigreen patterning, and about half of their actual size. Chemically it is green copper carbonate, CuCO3 Cu(OH)2 …   Glossary of Art Terms

  • malachite — malachitas statusas T sritis chemija apibrėžtis Mineralas. formulė Cu₂[(OH)₂|CO₃] atitikmenys: angl. malachite rus. малахит …   Chemijos terminų aiškinamasis žodynas


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