Minerales de Colección - Malaquita - Malachite - Congo - África скачать в хорошем качестве

Minerales de Colección - Malaquita - Malachite - Congo - África

+++ MALAQUITA +++ La malaquita es un mineral del grupo V (carbonatos) según la clasificación de Strunz, de fórmula química Cu2CO3(OH)2 (Dihidroxido de carbonato de cobre (II)). Posee un 57,0% de cobre. Su nombre viene del griego malaqh, que significa ‘malva’, en alusión a su color verde.​ En la antigüedad era usada como colorante, pero hoy en día su uso es más bien como piedra semipreciosa. También se la usa como mena para la extracción de cobre. Los yacimientos más importantes de este mineral están en Colombia, República Democrática del Congo, Sudáfrica, Zimbabue, Rusia, Namibia, Hungría, Estados Unidos y China . El color malaquita tiene como referente tanto la piedra malaquita como el colorante verde malaquita, por lo que su coloración puede variar entre el verde algo azulado como el que se muestra aquí abajo, hasta un verde azulado similar al color esmeralda. -- ENGLISH -- Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2. This opaque, green banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and spaces, deep underground, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur. 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". The mineral was given this name due to its resemblance to the leaves of the mallow plant. Malachite was extensively mined at the Great Orme mines in Britain 3,800 years ago using stone and bone tools. Archaeological evidence indicates that mining activity ended around 600 B.C.E with up to 1,760 tonnes of copper being produced from the mined Malachite. Archaeological evidence indicates that the mineral has been mined and smelted to obtain copper at Timna Valley in Israel for over 3,000 years. Since then, malachite has been used as both an ornamental stone and as a gemstone. In ancient Egypt the colour green (wadj) was associated with death and the power of resurrection as well as new life and fertility. Ancient Egyptians believed that the afterlife contained an eternal paradise which resembled their lives but with no pain or suffering, and referred to this place as the ‘Field of Malachite’. 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. This natural form of green pigment has been replaced by its synthetic form, verditer, among other synthetic greens. Malachite is also used for decorative purposes, such as in the Malachite Room in the Hermitage Museum, which features a huge malachite vase, and the Malachite Room in Castillo de Chapultepec in Mexico City. " The Tazza", a large malachite vase, one of the largest pieces of malachite in North America and a gift from Tsar Nicholas II, stands as the focal point in the centre of the room of Linda Hall Library. Malachite has also been used on the base of the FIFA World Cup Trophy. A 17th-century Spanish superstition held that having a child wear a lozenge of malachite would help them sleep, and keep evil spirits at bay. Malachite often results from the 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. Ural malachite is not being mined at present, but G.N Vertushkova reports the possible discovery of new deposits of malachite in the Urals. It is found worldwide including in the Democratic Republic of the Congo; Gabon; Zambia; Tsumeb, Namibia; Mexico; Broken Hill, New South Wales; Lyon, France; Timna Valley, Israel; and the Southwestern United States, most notably in Arizona. #MALAQUITA #malachite #congominerals #cobre #secundario