Chrysocolla malachite

Green pigments were chrysocolla, malachite, or other basic carbonates of copper and appianum, a green earth or chalk said to be a cheap and inferior color. 

The present description pertaining to copper refers to solvent extraction of copper at the Bluebird Mine, Miami. When the plant became operational in the first quarter of 1968 it used L1X 64, but L1X 64N was introduced in to its operation from late 1968. The ore consists of the oxidized minerals, chrysocolla and lesser amounts of azurite and malachite. A heap leaching process is adopted for this copper resource. Heap-leached copper solution is subjected to solvent extraction operation, the extractant being a solution of 7-8% L1X 64N incorporated in kerosene diluent. The extraction process flowsheet is shown in Figure 5.20. The extraction equilibrium diagram portrayed in Figure 5.21 (A) shows the condi-... 

A variety of mineral ores, mostly copper minerals such as malachite and chrysocolla, were probably the most used green pigments in the past. Various green minerals derived from metals other than copper, such as green earth (see below) were used in confined regions. 

Copper oxide mixed ore - Type 1. The main copper minerals found in these ores include malachite, pseudo-malachite, chrysocolla and some tenorite. These ores also may contain mainly siliceous gangue minerals, including spherocobaltite as the main cobalt minerals. The carbonaceous types also contain an appreciable amount of clay slime minerals. 

Mixed copper sulphide oxide ores. These contain varieties of both sulphide and oxide minerals, and are the most complex copper-bearing ores from a beneficiation point of view. The major copper minerals present in this ore type include bomite, chalcocite, covellite, malachite, cuprite and chrysocolla. In some cases, significant amounts of cobalt minerals are also present in this ore. 

Copper is the 26th most abundant element on Earth, but it is rare to find pure metallic deposits. It is found in many different types of mineral ores, many of which are close to the surface and easy to extract. It is found in two types of ores (1) sulfide ores, such as covellite, chalcopyrite, bornite, chalcocite, and enargite and (2) oxidized ores, such as tenorite, malachite, azurite, cuprite, chrysocolla, and brochanite. 

Heap (dump) acid leaching of copper sulfide ores is possible with the aid of microbial oxidation. Not all copper minerals are sulfidic, however— malachite, azurite, and chrysocolla are basic copper carbonates—and sulfuric acid heap leaching of low-grade copper carbonate ores can give solutions from which the Cu2+ ion can be separated by solvent extraction (Section 17.3) and copper metal obtained by electrowinning. 

Chrysocolla, Vitruvius says, is a green pigment brought from Macedonia and dug up in the vicinity of copper mines. As with Theophrastus, this is doubtless our malachite. Vitruvius states that those who cannot use chrysocolla on account of its cost employ a blue color (coeruleum) mixed with the plant called lutum, and obtain a very vivid green. Pliny also states this fact, but adds that it gives a very inferior color. 

This word chrysocolla of the ancients, which denotes malachite, was not confined to that mineral, as appears particularly from the extended description of Pliny. He mentions the substance dug from the mines in proximity to gold, but he also states that it is a liquid found in the shafts of mines—a slime hardened by the cold of winter till it haB the hardness of pumice. The most valued is from copper mines, the next best from silver mines, and that from the gold mines is inferior. In the mines also an artificial chrysocolla is made by allowing water to percolate into the veins during the winter and spring, and evaporating these in July and August. 

Copper, burned copper and flowers of copper with vinegar also yield ios. It may be assumed that as between verdigris (carbonate) and acetate of copper, no distinction was made ios of the Greeks and chrysocolla of the Latin writers cover both. Also the method of obtaining ios by rubbing copper and vinegar in a copper mortar is given by Dioscorides as previously by Theophrastus. When Theophrastus speaks of chrysocolla, he refers to malachite or to some other copper salts or mixtures of salts, vitriols, etc. 

It will be recalled that the term chrysocolla was applied also to malachite, verdigris and copper acetate, all of these being used for soldering gold. 

If, in the translation of the Bambergensis, uvam refers to the shape of grapes, one cannot understand why Pliny s text continues with Et tamen (Nevertheless). This sentence refers to the color of the material, and nevertheless does not make sense, if the reference to grapes concerns shape. This interpretation has led translators and chemical archaeologists (18) to identify chrysocolla with green malachite, which sometimes occurs as green grapes. ... 

According to the foregoing interpretation, chrysocolla of ancient times is neither malachite nor a blue copper silicate (the mineral now called chrysocolla) but is a yellow substance, possibly the yellow mineral cadmium sulfide, which appears as a coating on other minerals, chiefly zinc sulfide. This description fits Pliny s text, which describes gold solder (chrysocolla) as a liquid that flows from several mines to give a solid deposit. ... 

Surprisingly, we have found no comment on this sentence. If chrysocolla is malachite (copper carbonate), why can cuprous gold not be soldered with a brazing alloy containing copper, when copper can be dissolved in gold in... 

Native Chrysocolla from the Rhetian Alps, combined with Molochites, or Malachite. 

However, chrysocolla was also used historically as a term for malachite in classical and mediaeval literature such as the texts by Theophrastus (c. 315 bc), Vitruvius (first century BC) and Pliny (77 AD). For example, Vitruvius describes chrysocolla as coming from the copper mines of Macedonia. 

Cuprite is a cubic red copper(l) oxide mineral, with chemical formula CU2O. It is a common mineral which forms in the oxidised zones of copper ore deposits (e.g. in Cornwall, England Clifton, Arizona, USA Baha, Mexico Burra-Burra mine, South Australia Chessy, France Linares, Spain Salzburg and Tyrol, Austria Harz, Germany Attica, Greece). Cuprite often occurs with massive form or as well-formed cubes which may be interpenetrant. It may also form as long hair-like threads, in which case it is termed chalcotrichite. It is often found in association with limonite, chrysocolla and malachite (qq.v.) and is sometimes known as red oxide of copper (Rutley, 1988). 

Copper group Copper oxides and hydroxides group Azurite Chrysocolla Limonite Malachite Ochre Sienna Egyptian blue Freestone (1987) Oppenheim et al. (1970) Rutley (1988) 258-259 Scott (1997)... 

Copper silicate group Chrysocolla Dioptase Malachite Tenorite Dana (1932) 687 Evans Mrose (1977) Rouchon etal. (1990)... 

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