Cuprospinel

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Cuprospinel
General and classification
other names

IMA 1971-020

chemical formula
  • CuFe 3+ 2 O 4
  • (Cu, Mg) Fe 3+ 2 O 4
  • (Cu, Mg 2+ ) Fe 3+ 2 O 4
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.BB.05 ( 8th edition : IV / B.02)
02/07/02/06
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Fd 3 m (No. 227)Template: room group / 227
Lattice parameters a  = 8.37  Å
Formula units Z  = 8
Physical Properties
Mohs hardness 6.5 ( VHN 100 = 920-1081, average 985)
Density (g / cm 3 ) calculated: 5.25
Cleavage is missing
colour black, gray in incident light
Line color black
transparency opaque (opaque)
shine Metallic luster

Cuprospinell is a very rarely occurring minerals from the mineral class of "oxides and hydroxides" with the idealized chemical composition CuFe 3+ 2 O 4 , and thus chemically seen a copper - iron - oxide . However, since part of the copper in natural cuprospinels is often replaced by magnesium , the composition is also given in various sources as (Cu, Mg) Fe 3+ 2 O 4 . The elements indicated in the round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components of the mineral.

Cuprospinell crystallizes in the cubic crystal system , but has so far only been discovered in the form of irregular grains up to about 0.1 mm in size. Furthermore, it forms lamellar adhesions with hematite . The mineral is opaque in every form and shows a metallic sheen on the surfaces of the black crystallites . The stroke color of Cuprospinell is also black. In contrast , it appears gray under the incident light microscope .

Etymology and history

The synthetic compound CuFe 2 O 4 was probably first presented in 1950 by L. Weil, F. Bertaut and L. Bochirol. It was also found that this compound is dimorphic , since tetragonal and cubic modifications resulted in the synthesis.

The copper-iron oxide was first discovered in nature in 1971 by Ernest Henry Nickel in the Consolidated Rambler Mines on the Baie Verte peninsula in the Canadian province of Newfoundland and Labrador , who discovered the previously unknown mineral during the mineralogical investigation of strongly oxidized material from an ore dump found. Nickel gave the mineral the name Cuprospinell based on its copper content ( Latin: Cuprum ) and the structural relationship to the spinels and submitted its test results and the chosen name to the International Mineralogical Association (IMA) for examination (internal entry number of the IMA : 1971-020 ). This recognized the cuprospinell as an independent type of mineral. The first description was published in 1973 in the journal The Canadian Mineralogist .

The type material of the mineral is in the National Museum of Natural History in Washington, DC, USA, under the catalog no. 128673 kept.

classification

The current classification of the International Mineralogical Association (IMA) counts the cuprospinel to the spinel supergroup , where together with chromite , cochromite , coulsonite , dellagiustaite , deltalumite , franklinite , gahnite , galaxite , guit , hausmannite , hercynite , hetaerolite , jakobsite , maghemite , Magnesiochromite , magnesiocoulsonite , magnesioferrite , magnetite , manganochromite , spinel , thermoerogenite , titanomaghemite , trevorite , vuorelainenite and zincochromite form the spinel subgroup within the oxispinelle.

In the now outdated 8th edition of the mineral classification according to Strunz , the cuprospinell is not yet listed. Only in the Lapis mineral directory , which was revised and updated in 2018 by Stefan Weiß, which is still based on this classic system from Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system and mineral number. IV / B.02-50 . In the "Lapis system" this corresponds to the class of "oxides and hydroxides" and there the department "Oxides with a metal: oxygen ratio = 3: 4 (spinel type M 3 O 4 and related compounds)", where cuprospinel together with franklinite, Jacobite, magnesioferrite, magnetite and trevorite form the group of "chromite spinels".

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the IMA, also classifies the cuprospinel in the oxides division with a substance ratio of “metal: oxygen = 3: 4 and comparable”. This, however, is further divided according to the relative size of the participating cations , so that the mineral according to its composition in the subdivision to find "With only medium-sized cations" where it along with Brunogeierit , chromite, Cochromit, Coulsonit, Filipstadit , Franklinite, Gahnit , Galaxite, hercynite, jacobsite, magnesiochromite, magnesiocoulsonite, magnesioferrite, magnetite, manganochromite, nichromite (N), qandilite , spinel, trevorite, ulvöspinell , vuorelainenite and zinc chromite the "spinel group" with the system no. 4.BB.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the cochromite to the class of "oxides and hydroxides" and there in the "multiple oxides" section. Here it is together with magnesia ferrite, jacobsite, magnetite, franklinite, trevorite and brunogeierite in the " iron subgroup " with the system no. 07.02.02 to be found in the subsection “Multiple Oxides (A + B 2+ ) 2 X 4 , Spinel Group ”.

Chemism

The microprobe analysis of the Canadian type material showed an average composition of 65.7% Fe 2 O 3 , 27.8% CuO , 2.6% Al 2 O 3 , 1.7% FeO , 1.8% MgO , 0.7% ZnO , 0.6% CoO and 0.2% MnO . With a ratio of Fe 2+ to Fe 3+ according to the spinel structure, this corresponds to the empirical formula (Cu 0.80 Mg 0.10 Fe 2+ 0.05 Co 0.02 Zn 0.02 Mn 0.01 ) Σ = 1.00 (Fe 3+ 1.89 Al 0.11 ) Σ = 2.00 O 4 .

Crystal structure

Cuprospinell crystallizes cubically in the space group Fd 3 m (space group no. 227) , the lattice parameter a  = 8.37  Å and 8 formula units per unit cell . Template: room group / 227

properties

Cuprospinell resembles magnetite in most of its properties . Under the incident light microscope , however, the reflection color of magnetite, in contrast to cuprospinel, has a reddish tinge.

Education and Locations

At its type locality , the Consolidated Rambler Mines on the Canadian Baie Verte peninsula, the cuprospinel formed as an oxidation product in burning ore heaps . It was found there fused with hematite and in paragenesis with chalcopyrite , pyrite , pyrrhotite and sphalerite .

As a very rare mineral formation, Cuprospinell has only become known in a few samples. In addition to its type locality, only two other sites have been documented worldwide. In India, the mineral found in mineral samples from a sandbar at the river Mahanadi near Cuttack in the state of Odisha and Iran, it was found in the epithermal and niedersulfidischen Gold - deposit Chahnaly (also Chahnali ) at the volcano Bazman (also Kuh-e Bazman ) in the province of Sistan and Balochistan.

use

Because of its extreme rarity, Cuprospinell is only of interest to mineral collectors.

See also

literature

  • L. Weil, F. Bertaut and L. Bochirol: Propriétés magnétiques et structure de la phase quadratique du ferrite de cuivre . In: Le Journal de Physique et le Radium . tape 11 , 1950, pp. 208–212 ( available online at hal.archives-ouvertes.fr [PDF; 956 kB ; accessed on June 28, 2019]).
  • EH Nickel: The new mineral cuprospinel (CuFe 2 O 4 ) and other spinels from an oxidized ore dump at Baie Verte, Newfoundland . In: The Canadian Mineralogist . tape 11 , no. 5 , December 1973, pp. 1003–1007 ( rruff.info [PDF; 242 kB ; accessed on June 28, 2019]).
  • Michael Fleischer , Joseph A. Mandarino: New Mineral Names . In: American Mineralogist . tape 59 , 1973, pp. 381–384 ( minsocam.org [PDF; 478 kB ; accessed on June 28, 2019]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 506 (first edition: 1891).
  • Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 301 .

Web links

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  188 (English).
  2. ↑ a b c d e f g Cuprospinel . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 68  kB ; accessed on June 28, 2019]).
  3. ↑ a b c d Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  4. ^ David Barthelmy: Cuprospinel Mineral Data. In: webmineral.com. Retrieved June 28, 2019 .
  5. ↑ a b c EH Nickel: The new mineral cuprospinel (CuFe 2 O 4 ) and other spinels from an oxidized ore dump at Baie Verte, Newfoundland . In: The Canadian Mineralogist . tape 11 , no. 5 , December 1973, pp. 1003–1007 ( rruff.info [PDF; 242 kB ; accessed on June 28, 2019]).
  6. ↑ Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2019. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2019, accessed June 28, 2019 .
  7. ↑ Catalog of Type Mineral Specimens - C. (PDF 130 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed June 28, 2019 .
  8. ↑ Ferdinando Bosi, Cristian Biagioni, Marco Pasero: Nomenclature and classification of the spinel supergroup . In: European Journal of Mineralogy . tape 31 , no. 1 , September 12, 2018, p. 183–192 , doi : 10.1127 / ejm / 2019 / 0031-2788 (English).
  9. ↑ Paul Ramdohr : The ore minerals and their adhesions . 4th, revised and expanded edition. Akademie-Verlag, Berlin 1975, p.  969 .
  10. ↑ List of locations where cuprospinel was found in the Mineralienatlas and Mindat ( accessed : June 28, 2019).