# Paramelaconite > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Paramelaconite > Markdown URL: https://mediated.wiki/source/Paramelaconite.md > Source: https://en.wikipedia.org/wiki/Paramelaconite > Source revision: 1314810587 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Oxide mineral}} {{Infobox mineral | name = Paramelaconite | category = [Oxide mineral](/source/Oxide_mineral) | boxwidth = | boxbgcolor = | image = Paramelaconite-304492.jpg | imagesize = | caption = Paramelaconite from the [Copper Queen Mine](/source/Copper_Queen_Mine), Cochise County, Arizona, USA | formula = Cu{{su|b=2|p=I}}Cu{{su|b=2|p=II}}O3 (or Cu4O3){{sfn|Morgan et al.|1996|p=33}} | IMAsymbol = Pml{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |s2cid=235729616 |doi-access=free|url-access=subscription}} | molweight = | strunz = 4.AA.15 | dana = 4.6.4.1 | system = [Tetragonal](/source/Tetragonal_crystal_system) | class = Ditetragonal dipyramidal (4/mmm)
[H-M group](/source/H-M_group): (4/m 2/m 2/m) | symmetry = I41/amd {I41/a 2/m 2/d} | unit cell = a = 5.837 Å,
c = 9.932 Å; Z = 4 | color = Black to black with a slight purple tint
White with pinkish brown tint in reflected light | habit = Occurs as striated prismatic crystals; massive | twinning = | cleavage = None observed | fracture = [Conchoidal](/source/Conchoidal_fracture) | tenacity = Brittle | mohs = 4.5 | luster = Sub-adamantine, greasy, sub-metallic | polish = | refractive = | opticalprop = Uniaxial | birefringence = | 2V = | dispersion = | pleochroism = Weak | fluorescence= Not fluorescent | absorption = | streak = Brown-black | gravity = 6.04–6.11 (measured) | density = | melt = | fusibility = | diagnostic = | solubility = Soluble in [HCl](/source/hydrochloric_acid) and [HNO3](/source/Nitric_acid){{sfn|Koenig|1892|p=287}} | diaphaneity = Opaque | other = | references = }} '''Paramelaconite''' is a rare, black-colored [copper](/source/copper)(I,II) [oxide mineral](/source/oxide_mineral) with formula Cu{{su|b=2|p=I}}Cu{{su|b=2|p=II}}O3 (or Cu4O3). It was discovered in the [Copper Queen Mine](/source/Copper_Queen_Mine) in [Bisbee, Arizona](/source/Bisbee%2C_Arizona), about 1890. It was described in 1892 and more fully in 1941. Its name is derived from the Greek word for "near" and the similar mineral melaconite, now known as [tenorite](/source/tenorite). == Description and occurrence == [[File:Paramelaconite.jpg|left|thumb|[Type material](/source/Type_specimen_(mineralogy)) from the Copper Queen Mine held at the [A. E. Seaman Mineral Museum](/source/A._E._Seaman_Mineral_Museum)]] 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](/source/crystal_habit) or as crystals up to {{convert|7.5|cm|in|0|abbr=on}}. A yellow color is formed when the mineral is dissolved in [hydrochloric acid](/source/hydrochloric_acid), a blue color when dissolved in [nitric acid](/source/nitric_acid), and a slightly brown [precipitate](/source/precipitate) when exposed to [ammonium hydroxide](/source/ammonium_hydroxide).{{sfn|Koenig|1892|p=287}} When heated, paramelaconite breaks down into a mixture of tenorite and [cuprite](/source/cuprite).{{sfn|Frondel|1941|pp=657–658}} Paramelaconite is a very rare mineral; many specimens purported as such are in fact mixtures of cuprite and tenorite.{{sfn|O'Keeffe|Bovin|1978|p=180}} Paramelaconite forms as a secondary mineral in [hydrothermal](/source/Hydrothermal_synthesis) deposits of copper. It occurs in association with [atacamite](/source/atacamite), [chrysocolla](/source/chrysocolla), [connellite](/source/connellite), [cuprite](/source/cuprite), [dioptase](/source/dioptase), [goethite](/source/goethite), [malachite](/source/malachite), [plancheite](/source/plancheite), and [tenorite](/source/tenorite). The mineral has been found in Cyprus, the United Kingdom, and the United States. == Structure == Paramelaconite crystallizes in the [tetragonal crystal system](/source/tetragonal_crystal_system). Its [space group](/source/space_group) was correctly identified by Frondel as I41/amd. In 1978, O'Keeffe and Bovin determined the formula to be Cu4O3, specifically Cu{{su|b=2|p=I}}Cu{{su|b=2|p=II}}O3. There has been misunderstanding and misreporting of the mineral's [crystal structure](/source/crystal_structure), due in part to a typographical error in O'Keeffe and Bovin's paper and the commonality of choosing an incorrect origin for the I41/amd space group.{{sfn|Morgan et al.|1996|p=33}} At the same time as O'Keeffe and Bovin's report, a paper by Datta and Jeffery determined a structure for the mineral based on the incorrect formula Cu{{su|b=12|p=II}}Cu{{su|b=4|p=I}}O14.{{sfn|Morgan et al.|1996|p=33}}{{sfn|Datta|Jeffery|1978|p=22}} The formula originated from incorrectly assuming that Frondel's analysis was of a homogeneous crystal of paramelaconite.{{sfn|Morgan et al.|1996|p=33}} == Synthesis == The synthesis of microscopic paramelaconite was reported in 1986 as a product of the decomposition of [CuO](/source/CuO) in an [electron microscope](/source/electron_microscope). However, this method is not easily scaled up to produce samples large enough for study. Reduction of CuO and decomposition in a vacuum and controlled oxidation of Cu2O failed to synthesize the mineral. Experiments at the [National Bureau of Standards](/source/National_Bureau_of_Standards) using aqueous solutions up to 250 °C produced only Cu2O and CuO. Oxidation of copper or its alloys also does not produce paramelaconite, despite reports to the contrary.{{sfn|Morgan et al.|1996|p=35}} The first unequivocal synthesis of the mineral was achieved in the 1990s and published in 1996. The material produced was 35% Cu4O3, 27% Cu2O, and 38% CuO.{{sfn|Morgan et al.|1996|p=33}} The process consists of the leaching of copper or its oxides with concentrated [aqueous ammonia](/source/aqueous_ammonia) in a [Soxhlet extractor](/source/Soxhlet_extractor). The reaction forms a deep blue complex of [cupric](/source/cupric) ammonium that is converted to a residue of black oxide in the apparatus.{{sfn|Morgan et al.|1996|p=35}} == History == thumb|Drawing of a specimen found by Foote; the center pyramid is paramelaconite [Albert E. Foote](/source/Albert_E._Foote) visited the Copper Queen Mine about 1890,{{sfn|Frondel|1941|p=658}} where he obtained two specimens containing unknown minerals. He could only associate them with [anatase](/source/anatase), but he thought it unlikely that the minerals were any form of titanium oxide.{{sfn|Koenig|1892|p=284}} The specimens were sold to Clarence M. Bement at fifty dollars apiece, and with his permission, were studied by George Augustus Koenig.{{sfn|Frondel|1941|p=658}}{{sfn|Koenig|1892|p=284}} Bement's collection, including the specimens of paramelaconite, were purchased by [J. P. Morgan](/source/J._P._Morgan) in 1900 and given to the [American Museum of Natural History](/source/American_Museum_of_Natural_History).{{sfn|Morgan et al.|1996|p=33}}{{sfn|Frondel|1941|p=658}} Owing to its unique appearance, Koenig assigned the mineral as a new species.{{sfn|Koenig|1892|p=289}} His description of the mineral appeared in an 1892 publication of the [Academy of Natural Sciences of Philadelphia](/source/Academy_of_Natural_Sciences_of_Philadelphia).{{sfn|Koenig|1892|p=284}} He named the mineral ''paramelaconite'' from the Greek παρά, meaning "near", and the mineral melaconite (now known as [tenorite](/source/tenorite)), for its compositional similarity to melaconite.{{sfn|Koenig|1892|p=284}} At the time, however, the mineral was not recognized as a valid species.{{sfn|Frondel|1941|p=658}} Clifford Frondel studied the mineral in more detail and published his results in the journal ''American Mineralogist'' in 1941.{{sfn|O'Keeffe|Bovin|1978|p=180}}{{sfn|Frondel|1941|p=657}} When the [International Mineralogical Association](/source/International_Mineralogical_Association) was founded in 1959, paramelaconite was [grandfathered](/source/grandfather_clause) as a valid mineral species. 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](/source/A._E._Seaman_Mineral_Museum). Other specimens in the museum, labeled as originating from the Algomah Mine in [Ontonagon County, Michigan](/source/Ontonagon_County%2C_Michigan), were also found to contain paramelaconite.{{sfn|Williams|1962|p=778}} The [type material](/source/Type_specimen_(mineralogy)) is held at the A. E. Seaman Mineral Museum in Houghton, Michigan, the [American Museum of Natural History](/source/American_Museum_of_Natural_History) in New York City, [Harvard University](/source/Harvard_University) in Cambridge, Massachusetts, the [National Museum of Natural History](/source/National_Museum_of_Natural_History) in Washington, D.C., and the [Natural History Museum](/source/Natural_History_Museum%2C_London) in London. == References == {{reflist | colwidth = 30em | refs = {{cite encyclopedia | url = http://www.handbookofmineralogy.com/pdfs/paramelaconite.pdf | title = Paramelaconite | encyclopedia = Handbook of Mineralogy | editor1-first = John W. | editor1-last = Anthony | editor2-first = Richard A. | editor2-last = Bideaux | editor3-first = Kenneth W. | editor3-last = Bladh | editor4-first = Monte C. | editor4-last = Nichols | publisher = Mineralogical Society of America | location = Chantilly, VA | access-date = 2012-09-03 | archive-date = 2022-12-25 | archive-url = https://web.archive.org/web/20221225043111/https://www.handbookofmineralogy.com/pdfs/paramelaconite.pdf }} {{cite web | title = Paramelaconite | url = http://www.mindat.org/min-3098.html | publisher = Mindat | access-date = September 3, 2012 }} }} === Bibliography === * {{cite journal | last1=Datta|first1=N.|last2=Jeffery|first2=J. W.|title=The Crystal Structure of Paramelaconite, Cu{{su|b=12|p=2+}}Cu{{su|b=4|p=1+}}O14|journal=Acta Crystallographica Section B|year=1978|volume=34|pages=22–26|doi=10.1107/S056774087800223X }} {{subscription required}} * {{cite journal | last=Frondel|first=Clifford|title=Paramelaconite, a tetragonal oxide of copper|journal=American Mineralogist|date=November 1941|volume=26|issue=11|pages=567–672|url=http://rruff.info/uploads/AM26_657.pdf}} * {{cite journal | last=Koenig|first=George Augustus|title=On paramelaconite, and the associated minerals|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|year=1892|volume=43|pages=284–291|url=https://books.google.com/books?id=-MNLAAAAYAAJ&pg=PA284 }} * {{cite journal | last1=Morgan|first1=P. E. D.|last2=Partin|first2=D. E.|last3=Chamberland|first3=B. L.|last4=O'Keeffe|first4=M.|title=Synthesis of Paramelaconite: Cu4O3|journal=Journal of Solid State Chemistry|date=January 5, 1996|volume=121|issue=1|pages=33–37|doi=10.1006/jssc.1996.0005 | ref = {{sfnRef|Morgan et al.|1996}} |bibcode = 1996JSSCh.121...33M }} {{subscription required}} * {{cite journal | last1=O'Keeffe|first1=M.|last2=Bovin|first2=J.-O.|title=The crystal structure of paramelaconite Cu4O3|journal=American Mineralogist|date=January–February 1978|volume=63|issue=12|pages=180–185|url=http://www.minsocam.org/ammin/AM63/AM63_180.pdf}} * {{cite journal | last=Williams|first=Sidney A.|title=Paramelaconite and associated minerals from the Algomah mine, Ontonagon County, Michigan|journal=American Mineralogist|date=May–June 1962|volume=47|issue=5–6|pages=778–779|url=http://www.minsocam.org/ammin/AM47/AM47_778.pdf}} === Further reading === * {{cite journal|last1=Pinsard-Gaudart|first1=L.|last2=Rodríguez-Carvajal|first2=J.|last3=Gukasov|first3=A.|last4=Monod|first4=P.|title=Magnetic properties of paramelaconite (Cu4O3): A pyrochlore lattice with ''S'' = 1/2|journal=Physical Review B|date=1 March 2004|volume=69|issue=10|article-number=104408|doi=10.1103/PhysRevB.69.104408|bibcode = 2004PhRvB..69j4408P }} {{subscription required}} == External links == {{Commonscat-inline|Paramelaconite}} Category:Tetragonal minerals Category:Minerals in space group 141 Category:Copper(I,II) minerals Category:Oxide minerals Category:Minerals described in 1892 --- Adapted from the Wikipedia article [Paramelaconite](https://en.wikipedia.org/wiki/Paramelaconite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Paramelaconite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.