Paramelaconite
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Paramelaconite | |
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![]() Paramelaconite from the Copper Queen Mine, Cochise County, Arizona, USA | |
Allgemein | |
Kategorie | Mineral |
Formula (repeating unit) | Cu21+Cu22+O3[1] |
Strunz classification | 4.AA.15 |
Dana classification | 4.6.4.1 |
Crystal system | Tetragonal |
Space group | Ditetragonal dipyramidal H-M group: 4/mmm (4/m 2/m 2/m) Space group: I41/amd {I41/a 2/m 2/d} |
Unit cell | a=5.837 Å, c=9.932 Å Z=4[1] |
Identification | |
Color | Black to black with a slight purple tint White with pinkish brown tint in reflected light |
Cleavage | None observed |
Fracture | Conchoidal |
Tenacity | Brittle |
Mohs scale hardness | 4.5 |
Luster | Sub-adamantine, greasy, sub-metallic |
Streak | Brown-black |
Diaphaneity | Opaque |
Optical properties | Uniaxial[1] |
Pleochroism | Weak |
Ultraviolet fluorescence | Not fluorescent |
Solubility | Soluble in HCl and HNO3[2] |
References | [3] |
Paramelaconite is a rare mineral with formula Cu21+Cu22+O3. It was discovered in the Copper Queen Mine in the U.S. State of Arizona and described in 1892. Its name is derived from the Greek word for "near" and the similar mineral melaconite, now known as tenorite.
Description and occurrence
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/7a/Paramelaconite.jpg/220px-Paramelaconite.jpg)
Paramelaconite is black to black with a slight purple tint in color, and is white with a pinkish brown tint in reflected light. The mineral occurs with massive habit or as crystals up to 7.5 centimetres (3.0 in).[1] A yellow color is formed when the mineral is dissolved in hydrochloric acid, a blue color when dissolved in nitric acid, and a slightly brown precipitate when exposed to ammonium hydroxide.[2] When heated, paramelaconite breaks down into a mixture of tenorite and cuprite.[4]
Paramelaconite, a very rare mineral, forms as a secondary mineral in hydrothermal deposits of copper. It occurs in association with atacamite, chrysocolla, connellite, cuprite, dioptase, goethite, malachite, plancheite, and tenorite.[1] The mineral has been found in Cyprus, the United Kingdom, and the United States.[3]
Structure
History
A. E. Foote visited the Copper Queen Mine in the early 1890s, where he obtained two specimens containing unknown minerals. He could only associate them with anatase, but he thought it unlikely that the minerals were any form of titanium oxide. The specimens became part of Clarence M. Bement's collection and were studied by George Augustus Koenig.[5] As part of his collection, the specimens later became the property of the American Museum of Natural History.[6]
Owing to its unique appearance, Koenig assigned the mineral as a new species.[7] His description of the mineral appeared in an 1892 publication of the Academy of Natural Sciences of Philadelphia.[5] He named the mineral paramelaconite from the Greek παρά, meaning "near", and the mineral melaconite (now known as tenorite), for its compositional similarity to melaconite.[3][5] At the time, however, the mineral was not recognized as a valid species.[6]
Clifford Frondel studied the mineral in more detail and published his results in 1941.[8]
In the early 1960s, the third known specimen of paramelaconite was discovered from the Copper Queen Mine; Koenig donated it to the A. E. Seaman Mineral Museum. Other specimens in the museum, labeled as originating from the Algomah Mine in Ontonagon County, Michigan, were also found to contain paramelaconite.[9]
When the International Mineralogical Association was founded, paramelaconite was grandfathered as a valid mineral species.[3]
The type material is held at the A. E. Seaman Mineral Museum in Houghton, Michigan, the American Museum of Natural History in New York City, Harvard University in Cambridge, Massachusetts, the National Museum of Natural History in Washington, D.C., and the Natural History Museum in London.[1]
References
- ^ a b c d e f Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (eds.). "Paramelaconite" (PDF). Handbook of Mineralogy. Chantilly, VA: Mineralogical Society of America.
- ^ a b Koenig 1892, p. 287
- ^ a b c d "Paramelaconite". Mindat. Retrieved September 3, 2012.
- ^ Frondel 1941, pp. 657–658
- ^ a b c Koenig 1892, p. 284
- ^ a b Frondel 1941, p. 658
- ^ Koenig 1892, p. 289
- ^ Frondel 1941, p. 657
- ^ Williams 1962, p. 778
Bibliography
- Frondel, Clifford (1941). "Paramelaconite, a tetragonal oxide of copper" (PDF). American Mineralogist. 26 (11): 567–672.
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ignored (help) - Koenig, George Augustus (1892). "On paramelaconite, and the associated minerals". Proceedings of the Academy of Natural Sciences of Philadelphia. 43: 284–291.
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(help) - Morgan, P. E. D.; Partin, D. E.; Chamberland, B. L.; O'Keeffe (January 5, 1996). "Synthesis of Paramelaconite: Cu4O3". Journal of Solid State Chemistry. 121 (1): 33–37. doi:10.1006/jssc.1996.0005.
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(help) (subscription required) - O'Keeffe, M.; Bovin, J.-O. (1978). "The crystal structure of paramelaconite Cu4O3" (PDF). American Mineralogist. 63 (12): 180–185.
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ignored (help) - Williams, Sidney A. (1962). "Paramelaconite and associated minerals from the Algomah mine, Ontonagon County, Michigan" (PDF). American Mineralogist. 47 (5–6): 778–779.
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External links
Media related to Paramelaconite at Wikimedia Commons