Magnesia ferrite

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Magnesia ferrite
Magnesioferrite-755795.jpg
Magnesioferrite in matrix from Långban , Filipstad, Värmland, Sweden (size: 9.5 cm × 6 cm × 5 cm)
General and classification
other names
  • Magneferrite
  • Magnoferrite
chemical formula MgFe 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.01b)
02/07/02/01
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
Formula units Z  = 8
Twinning after {111} as contact twins in the spinel law
Physical Properties
Mohs hardness 6 to 6.5
Density (g / cm 3 ) measured: 4.55 to 4.65; calculated: 4,556 ( VHN 100 = 899 to 910)
Cleavage after {111}
Break ; Tenacity uneven; brittle
colour brownish black to black
Line color dark red to blackish red
transparency opaque
shine Metallic luster
magnetism strong magnetic

Magnesioferrite (also magnoferrite or magnoferrite ) is a rarely occurring mineral from the group of spinels within the mineral class of " oxides and hydroxides " with the chemical composition MgFe 2 3+ O 4 and is therefore chemically a magnesium - iron - oxide .

Magnesia ferrite crystallizes in the cubic crystal system , but rarely develops well-formed, octahedral crystals and contact twins according to the spinel law up to about 5 mm in size. It is mostly found in the form of granular to massive mineral aggregates of brownish-black to black color and a metallic sheen on the surfaces. The mineral is generally opaque, but can be translucent in thin slivers.

Magnesia ferrite forms a mixed series with magnetite .

Etymology and history

Magnesian ferrite was first discovered in the volcanic lavas on Vesuvius in the Italian province of Naples. It was first described in 1859 by Karl Friedrich Rammelsberg , who named the mineral after its main components magnesium and iron ( Latin: ferrum ).

Type material for magnesia ferrite is not defined.

classification

The current classification of the International Mineralogical Association (IMA) is one of the Magnesioferrit to spinel supergroup , where he together with chromite , Cochromit , Coulsonit , Cuprospinell , Franklinite , Gahnit , Galaxit , Hercynit , Jakobsit , Magnesiochromite , Magnesiocoulsonit , magnetite , Manganochromit , spinel , Trevorit , Vuorelainenit and Zincochromit forming the spinel subgroup within the Oxispinelle.

Already in the outdated, but still in use 8th edition of the mineral classification according to Strunz , the magnesia ferrite belonged to the mineral class of "oxides and hydroxides" and there to the department of "compounds with M 3 O 4 - and related compounds", where together with franklinite, Jakobsite, magnetite and trevorite the group of "iron (III) spinels" with the system no. IV / B.01b .

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.02-10 . In the "Lapis system" this also corresponds to the department "Oxides with a ratio of metal to oxygen = 3: 4 (spinel type M 3 O 4 and related compounds)", where magnesioferrite together with cuprospinel, franklinite, jacobsite, magnetite and trevorite form the group which forms "ferrite 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 magnesioferrite in the oxides division with a molar ratio of “metal: oxygen = 3: 4 and comparable”. This, however, is further divided according to the relative size of the participating cations , is 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, Cuprospinell, Filipstadit , Franklinite, Gahnite, galaxite, hercynite, jacobsite, magnesiochromite, magnesiocoulsonite, magnetite, manganochromite, nichromite (N), qandilite , spinel, trevorite, ulvöspinell , vuorelainenite and zincochromite 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 , also assigns magnesia ferrite to the class of "oxides and hydroxides" and there in the section "multiple oxides". Here it is together with brunogeierite, cuprospinel, franklinite, jacobsite, magnetite and trevorite 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 ”.

Crystal structure

Magnesia ferrite crystallizes cubically in the space group Fd 3 m (space group no. 227) with the lattice parameter a  = 8.38  Å and eight formula units per unit cell . Template: room group / 227

Education and Locations

Magnesia ferrite crystals from Ochtendung in the Eifel in a very rare hexakisoctahedral formation

Usually magnesia ferrit forms on fumaroles or metamorphically when marl and coal heaps are burned down . It can also be found as an accessory component of some kimberlites , carbonatites and alkaline gabbros . Accompanying minerals include hematite , with which magnesioferrite regularly grows , as well as titanomagnetite and iron-containing diopsids .

As a rather rare mineral formation, magnesia ferrite can sometimes be abundant at various sites, but overall it is not very common. So far, around 100 sites for magnesia ferrite have been documented (as of 2018). In addition to its type locality Vesuvius, magnesia ferrit also occurred in Italy in the nearby Villa Inglese quarry near Torre del Greco and Sant'Anastasia on Monte Somma in Campania, in Colle Cimino near Marino and Corcolle near Tivoli in Latium, in various volcanic rocks from Etna and Stromboli in Sicily as well as in the Vispi quarry near San Venanzo and in the sub-volcanic rocks near Colle Fabbri near Spoleto in Umbria.

In Germany, magnesioferrite was found in the Orberg quarries near Schelingen and Badloch am Badberg near Vogtsburg in the Kaiserstuhl with Sövitic carbonatites in Baden-Württemberg; on the basalt cone Parkstein in Bavaria; Found in various locations in the district of Mayen-Koblenz (Wingertsberg, Ettringer Bellerberg , Nickenich , Wannenköpfe) and in the Vulkaneifel (Emmelberg, Feuerberg, Rother Kopf) in Rhineland-Palatinate and on the dump of the Lichtenberg opencast mine near Ronneburg in Thuringia. In addition, magnesia ferrite was found to be a component of the Kiel meteorite , an L6 chondrite that fell in 1962 near the town of the same name in Schleswig-Holstein.

In Austria, the mineral could only be found in the Spittal an der Drau district near Millstätter See in Carinthia; can be discovered in the basalt quarries on Stradner Kogel and Klöch as well as in rock samples that arose during the construction of the Kirchdorftunnel near Kirchdorf (municipality of Pernegg an der Mur ) in Styria. It was also found in the Tyrolean community of Prägraten am Großvenediger .

Abundant finds of magnesia ferrite are also known from Ilimpeja in the Russian region of Central Siberia .

Other locations include China, the Israeli Negev desert , Canada, Poland, the Czech Republic and the USA.

See also

literature

  • C. Rammelsberg: About the so-called octahedral iron luster from Vesuvius, and about the formation of magnetic iron by sublimation . In: Annals of Physics and Chemistry . tape 107 , 1859, pp. 451–454 ( rruff.info [PDF; 236 kB ; accessed on September 23, 2019]).
  • H. St. C. O'Neill, H. Annersten, D. Virgo: The temperature dependence of the cation distribution in magnesioferrite (MgFe2O4) from powder XRD structural refinements and Mössbauer spectroscopy . In: American Mineralogist . tape 77 , 1992, pp. 725-740 ( rruff.info [PDF; 2.1 MB ; accessed on September 23, 2019]).

Web links

Commons : Magnesioferrite  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  503 (first edition: 1891).
  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.  188 (English).
  3. ↑ a b David Barthelmy: Magnesioferrite Mineral Data. In: webmineral.com. Retrieved September 23, 2019 .
  4. ↑ a b c d e f Magnesian ferrite . 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; 72  kB ; accessed on September 23, 2019]).
  5. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  6. ↑ Catalog of Type Mineral Specimens - M. (PDF 124 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed September 23, 2019 .
  7. ↑ Cristian Biagioni, Marco Pasero: The systematics of the spinel-type minerals: An overview . In: American Mineralogist . tape 99 , no. 7 , 2014, p. 1254–1264 , doi : 10.2138 / am.2014.4816 (English, preliminary version online at minsocam.org [PDF; 4.6 MB ; accessed on September 23, 2019]).
  8. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed September 23, 2019 .
  9. ↑ 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.  388 .
  10. ↑ Localities for Magnesian Ferrite. In: mindat.org. Hudson Institute of Mineralogy, accessed September 23, 2019 .
  11. ↑ Stefan Schorn u. a .: Kiel. Meteorite fall from 1962: simple chondrite. In: mineralienatlas.de. Mineral Atlas , accessed September 23, 2019 .
  12. ^ Meteorite Kiel. In: lpi.usra.edu. Meteoritical Bulletin Database, accessed September 23, 2019 .
  13. ↑ List of locations for magnesioferrite in the Mineralienatlas and Mindat