Atacamite is one of the minerals which has a tendency of distribution in the desert areas.It was generally discovered in the Atacama Desert which is considered as the hardest areas in the world. This mineral was generally discovered in the year of 1801 in the Atacama area in the country of Chile. It can be sometimes referred to by the names likeAlacamite, Marcylite, Kupfert And or Arsenio (I, Dossett &D, I, Green, 1998).The mineral of Atacamite has one of the complex structures in nature. The structure ofAtacamite mineral can be described by characterizing both its physical and chemical structure. Atacamite mineral is a mineral which has the chemical formula of Cu2Cl (OH) 3.This mineral usually.
This mineral is a halide which forms the natural salts. The atacamite is attractive in nature. This mineral is a polymorphic mineral which has the same chemistry with the botallackite and paratacamite. The color of the catamite is characterized by the shades of deep green color or black green. It has the cleavage which can be characterized as being perfect and that cleavage is of the size of 010.
This mineral has the density of 3.76-3.78 with an average of 3.76.It is one of the mineral which has the diaphaneity ranging from transparent to transluncent. The fractures on it are characterized as being conchoidal in nature, which is the fractures are characterized by the smooth curves. The crystals of these minerals are composed of the mineral fibers. This mineral has been found to be generally occurring as cathedral crystals. In reference to its hardness, the atacamite has the degree of hardness which ranges from 3-3.5.The light characteristic of this mineral is that it’s a non-luminescent in nature. On the other hand this mineral has the apple green streak with the luster of adamantine.
The mineral species which Occur in nature with this atacamite structure is copper which belongs to the halide group (N.J. Elton, 1998). This occurrence of the copper species has been attributed by the fact that atacamite minerals have an occurrence in the desert areas at the zone of the oxidized deposits of the copper mineral. At the other hand they are formed in the fumaroles deposits. On the other hand the atacamite minerals are regarded as the minerals which are formed by the oxidation of the copper minerals. Sometimes the atacamite has been considered as altered products of copper and bronze.
The solid solution which occurs between the members of the atacamite mineral group is the oxy-halide in nature. It contains oxygen and hydroxides as their chemical composition. They are generally considered to be aqueous in nature (T. F. Bridges & B. Young, 1998)
The techniques which are used to analyze the composition of the atacamite structure vary from one analytical laboratory to another. The mostly commonly used methods include the use of the photographic light polarizing microscopy, radioactivity techniques, spectroscopic techniques, Mohs scale method and the crystallization technique. In the technique of the microscopy the atacamite minerals are observed as having crystals with the bright greenish or the blackish greenish colour. At the same time this mineral shows displays which are vitreous luster in nature, thus it appears as the shape of the broken glass. At the same time if this atacamite specimen is passed across the streak plate which is white in color it will form a pale green streak. Moreover when this mineral specimen is observed in crossed nicols under the polarizing microscopy it shows the crystals which are so complete. At some instances the cleavages are observed in one direction. There is dispersion which is so strong when the atacamite crystals are observed under the polarized microscopy. Another method which is used to analyze the hardness of this mineral is the use of the Mohs scale method.This method is used to measure the hardness of the mineral. The hardness of these mineral ranges from 3.0 to 3.5 respectively. Thus this mineral can be regarded as being soft in nature.
Crystallization technique can be used to analyze the composition of this mineral. The atacamite mineral usually will crystallize under the orthorhombic mediums. The crystals formed consist of three perpendicular axes with differing lengths respectively. The crystals formed are slender in nature and have circular shapes. Thus circular crystals have the needle grains which are usually elongated in nature. On the other hand the crystals formed may be granular in nature and vertically striated.
The x-ray crystallography technique can be used to analyze the composition of the atacamite mineral. Under this technique the three dimensional structures are observed. This technique is used since the visible light has a disadvantage of not observing some atoms, thus this is substituted with the electromagnetic light which will have the analysis advantage. Consequently the spectroscopy technique can be used to analyze the composition and structure of the atacamite mineral. Under this technique the Raman spectroscopy is used.The Raman spectroscopy involves the use of the scattering light to analyze the atomic nature of the minerals (D. P. Shoemaker & C. W. Garland, 2004).
The other method which can be used in the analysis of the atacamite mineral is the radioactivity technique. Under this method, radioactive equipment such as the GM tube are used. The atacamite mineral does not absorb the radioactive waves hence it does not appear the black color possessed by the radioactive materials.
Bibliography
D. P. Shoemaker, C. W. Garland and J. W. Nibler, Experiments in Physical Chemistry, 6th ed., McGraw-Hill, New York, NY, pp. 389 – 397.
D.I. Green and J.R. Nudds. (1998), Harmotome from Brownley Hill Mine, Nenthead, Cumbria, England.
Dossett and D.I. Green. (1998), Atacamite, botallackite and cumengeite from Abersoch, Gwynedd, Wales.
N.J. Elton. (1998), Barbosalite, frondelite and other phosphates from Gunheath china clay pit, St Austell, Cornwall, England.
T.F. Bridges and B. Young. (1998), Supergene minerals of the Northern Pennine Orefield – A review.