Coulsonite

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Coulsonite
General and classification
other names

Vanadomagnetite

chemical formula
  • Fe 2+ V 3+ 2 O 4
  • FeO · V 2 O 3
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.BB.05 ( 8th edition : IV / B.01d)
07.02.04.02
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  = 8.30  Å
Formula units Z  = 8
Physical Properties
Mohs hardness 4.5 to 5
Density (g / cm 3 ) measured: 5.17 to 5.20; calculated: 5.15
Cleavage is missing
Break ; Tenacity brittle
colour blue-gray, also light gray in incident light
Line color dark brown to black
transparency opaque (opaque)
shine Metallic luster

Coulsonit is a rarely occurring minerals from the mineral class of "oxides and hydroxides" with the chemical composition of Fe 2+ V 3+ 2 O 4 , and thus chemically seen a iron - Vanadium - oxide .

Coulsonite crystallizes in the cubic crystal system , but has so far only been discovered in the form of tiny crystals less than 1 mm in diameter with only partially developed crystal surfaces and as segregation lamellae along the octahedral surfaces {111} in magnetite . The mineral is opaque in every form and shows a metallic sheen on the surfaces of the blue-gray, in incident light also light-gray, crystals . In contrast to the surface color , the line color of Coulsonite is dark brown to black.

Etymology and history

Under the name vanado-magnetite (German: vanadomagnetite ) used by Alexander Heron , the mineral was known from finds from India as early as 1936, but it was only insufficiently described. A year later it was given the name Coulsonite, which is still valid today. Coulsonite is named after the geologist and employee of the Indian Geological Survey Arthur Lennox Coulson (1898–1955).

The complete first description as an independent mineral type was made in 1962 by Arthur Sears Radtke (1936-2004) on the basis of mineral samples from the Buena Vista iron mine in Churchill County of the US state Nevada , which is accordingly considered a type locality for coulsonite.

Type material for this mineral is not defined.

classification

The current classification of the International Mineralogical Association (IMA) counts the coulsonite to the spinel supergroup , where together with chromite , cochromite , cuprospinel , 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.

Already in the outdated, but still in use 8th edition of the mineral classification according to Strunz , the cochromite belonged to the mineral class of "oxides and hydroxides" and there to the department "compounds with M 3 O 4 - and related compounds", where he joined the group with Ulvöspinell the "vanadium and titanium spinels" with the system no. IV / B.01d .

In the last revised and updated Lapis mineral directory by Stefan Weiß in 2018 , which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral was given the system and mineral number. IV / B.04-20 . In the "Lapis system" this also corresponds to the department "Oxides with a metal: oxygen ratio = 3: 4 (spinel type M 3 O 4 and related compounds)", where coulsonite together with brunogeierite , magnesiocoulsonite, qandilite , ulvöspinell and vuorelainenite form the group which forms "V / Ti / Ge spinels".

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the IMA until 2009, also classifies coulsonite in the oxides division with a substance ratio of “metal: oxygen = 3: 4 and comparable”. However, this is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With only medium-sized cations”, where it can be found together with brunogeierite, chromite, cochromite, cuprospinel, filipstadite , franklinite, gahnite , 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 magnesiocoulsonite and vuorelainenite in the " vanadium subgroup " with system no. 07.02.04 can be found in the subsection “Multiple oxides (A + B 2+ ) 2 X 4 , spinel group”.

Chemism

In chemically pure form, which is only realized in synthesis, coulsonite (FeV 2 O 4 ) consists of 25.19% iron (Fe), 45.95% vanadium (V) and 28.86% oxygen (O). In the oxide formula (FeO · V 2 O 3 ) this corresponds to 32.40% FeO and 67.60% V 2 O 3 .

The analysis of the samples from the Buena Vista Hills showed that a small proportion of the V 3+ was replaced ( substituted ) by Fe 3+ , which corresponds to the empirical composition Fe 2+ 1.00 (V 3+ 1.07 Fe 3+ 0.01 ) Σ = 1.08 O 4.24 corresponds. Further analyzes on samples from Kalgoorlie in Australia showed that part of the V 3+ can also be replaced by titanium . The empirical formula is given here accordingly with Fe 2+ 1.03 (V 3+ 1.84 Ti 0.13 ) Σ = 1.97 O 4.02 .

Crystal structure

Coulsonite crystallizes cubically in the spinel structure with the space group Fd 3 m (space group no. 227) , the lattice parameter a  = 8.30  Å and 8 formula units per unit cell . Template: room group / 227

Education and Locations

Coulsonite often forms together with chlorine-rich scapolite in magnetite-containing veins that run through metamorphosed igneous rocks . Other accompanying minerals can include apatite , titanite , various chlorites , hornblende and muscovite .

As a rare mineral formation, coulsonite could only be detected at a few sites, although around 15 sites have been documented so far (as of 2018). In addition to its type locality , the Buena Vista iron mine in Churchill County, the mineral in Nevada could also be found in the Buena Vista Hills in neighboring Pershing County . In addition, coulsonite was found in the secondary mixes of the gold and silver soaps of the "Colorado Creek" pits in the Innoko District in the Yukon-Koyukuk Census Area of Alaska and in the serpentinites of an unnamed iron-vanadium mineralization in the Diablo Mountain range near New Idria in Fresno County of California.

Within Europe, coulsonite has so far only come from a mine near Vihanti in the Finnish Maakunta ( landscape ) of northern Ostrobothnia , the "Lengenbach mine" in the Binn valley in the Swiss canton of Valais and in the sedimentary-exhalative deposits near the Cistercian monastery Monestir de Santa Maria de Poblet (English: Poblet Monastery ) in the Catalan province of Tarragona known.

Other well-known sites are in the Indian state of Bihar , the Amur Oblast in the Far East Federal District and the Murmansk Oblast in the Northwestern Federal District. In addition, coulsonite was found in the meteorites Efremovka near Pavlodar in Kazakhstan and Allende near Pueblito de Allende in Mexico.

See also

literature

  • AM Heron: General report for 1936 . In: Records of the geological survey of India . tape 71 , 1936, pp. 44 .
  • Arthur S. Radtke: Coulsonite, FeV 2 O 4 , a spinel-type mineral from Lovelock, Nevada . In: The American Mineralogist . tape 47 , 1962, pp. 1284–1291 ( minsocam.org [PDF; 523 kB ; accessed on June 28, 2019]).
  • J. Kent Perry: Discussion of "Coulsonite" by Arthur S. Radtke . In: The American Mineralogist . tape 47 , 1963, pp. 1284–1291 ( minsocam.org [PDF; 358 kB ; accessed on June 28, 2019]).
  • B. Reuter, E. Riedel, P. Hug, D. Arndt, U. Geisler, J. Behnke: On the crystal chemistry of vanadium (III) spinels . In: Journal of Inorganic and General Chemistry . tape 369 , no. 3-6 , October 1969, pp. 306-312 , doi : 10.1002 / zaac.19693690320 .

Web links

Individual evidence

  1. ↑ a b Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p.  386 .
  2. ↑ a b c d 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.  189 .
  3. ↑ a b 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 .
  4. ^ A b c Arthur S. Radtke: Coulsonite, FeV 2 O 4 , a spinel-type mineral from Lovelock, Nevada . In: The American Mineralogist . tape 47 , 1962, pp. 1284–1291 ( minsocam.org [PDF; 523 kB ; accessed on June 28, 2019]).
  5. ^ A b David Barthelmy: Coulsonite Mineral Data. In: webmineral.com. Retrieved June 28, 2019 .
  6. ↑ a b c d e f g h i Coulsonite . 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; 70  kB ; accessed on June 28, 2019]).
  7. ↑ a b 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 .
  8. ↑ JA Dunn: Coulsonite . In: Memoirs of the Geological Survey of India . tape 69 , 1937, pp. 21 .
  9. ^ Grave slab of Arthur Sears Radtke with the chemical formula of the Radtkeit named after him. In: findagrave.com. Find A Grave, accessed June 28, 2019 .
  10. ↑ 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).
  11. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed April 25, 2019 .
  12. ↑ Coulsonite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 28, 2019 .
  13. ↑ Find location list for coulsonite in the Mineralienatlas and Mindat