Qandilit

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Qandilit
General and classification
other names
  • IMA 1980-046
  • Magnesia titanate spinel
chemical formula
  • (Mg, Fe 3+ , Fe 2+ ) 2 (Ti 4+ , Fe 3+ , Al) O 4
  • (Mg, Fe 2+ ) 2 (Ti, Fe 3+ , Al) O 4
  • Mg 2 Ti 4+ O 4
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.BB.05 ( 8th edition : IV / B.04)
02/07/05/01
Similar minerals Magnetite , magnesia ferrite
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  = 8.40  Å
Formula units Z  = 8
Physical Properties
Mohs hardness 7 (VHN 100 = 960 to 1045)
Density (g / cm 3 ) measured: 4.03; calculated: 4.04
Cleavage completely after {111}
Break ; Tenacity brittle
colour black
Line color black
transparency opaque (opaque)
shine Metallic luster
magnetism strong magnetic
Other properties
Chemical behavior soluble in hot 50% hydrochloric acid (HCl)

Qandilit (pronounced Kandilit ) is a very rarely occurring minerals from the mineral class of "oxides and hydroxides" with the idealized chemical composition of Mg 2 Ti 4+ O 4 and is thus chemically seen a magnesium - titanium - oxide . Structurally, however, qandilite belongs to the group of spinels .

Qandilite crystallizes in the cubic crystal system and develops octahedral crystals up to about 2.3 mm in size, but also occurs in the form of granular mineral aggregates . The mineral is opaque (in any form opaque ) and displays on the surfaces of black crystals have a metallic luster . His stroke color is also black. Under the reflected light microscope , however, qandilit appears gray with a pale pink tinge.

Etymology and history

Was first discovered in the Qandilit as Qandil group designated metamorphic rocks on the mountain Dupezeh in Qala Diza ( Qeladze , قلعة دزة) in the governorate as-Sulaymaniyah in the autonomous region of Kurdistan in northern Iraq . It was first described in 1985 by HM Al-Hermezi, who named the mineral after its type locality .

The type material of the mineral is at the University of Strathclyde in Glasgow and the Royal Museum in Edinburgh in Scotland, in the National Museum of Natural Sciences in Tokyo (Japan) as well as in the Mines ParisTech (also École des mines de Paris ) and in the Muséum national d'histoire naturelle kept in Paris (France).

classification

The current classification of the International Mineralogical Association (IMA) is one of the Qandilit to spinel supergroup , where he together with Ahrensit , Brunogeierit , Filipstadit , ringwoodite and Ulvöspinell forms the Ulvöspinell subgroup within the Oxispinelle.

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the qandilite belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with a metal: oxygen ratio = 3: 4 (spinel type M 3 O 4 and related compounds) ", where together with brunogeierite, coulsonite , magnesiocoulsonite , ulvöspinell and vuorelainenite, the group of" V / Ti / Ge spinels "with the system no. IV / B.04 .

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the IMA, also classifies the qandilit in the oxides division with a substance ratio of “metal: oxygen = 3: 4 and comparable”. This is, however, further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the subsection "With only medium-sized cations", where it can be found together with brunogeierite, cochromite , coulsonite , cuprospinell , chromite , filipstadite, franklinite , Gahnite , galaxite , hercynite , jacobsite , magnesiochromite , magnesiocoulsonite , magnesioferrite , magnetite , manganochromite , nichromite (N), 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 , assigns the qandilite to the class of "oxides and hydroxides" and there in the department of "multiple oxides". Here he is together with Ulvöspinell in the " Titan subgroup " with system no. 07.02.13 to be found in the subsection "Multiple oxides (A + B 2+ ) 2 X 4 , spinel group".

Chemism

The idealized, theoretical compound Mg 2 TiO 4 consists of 30.29% by weight of magnesium (Mg), 29.83% by weight of titanium (Ti) and 39.88% by weight of oxygen (O). However, the electron beam microanalysis of samples from the type locality Qandil, Dupezeh also contained a significant proportion of iron in the form of 28.27% Fe 2 O 3 and 10.32% FeO . In addition, there are small admixtures of 4.83% Al 2 O 3 and 0.76% MnO and traces of 0.02% silicon dioxide (SiO 2 ). Based on four oxygen atoms, the empirical formula (Mg 1.32 Fe 3+ 0.41 Fe 2+ 0.26 Mn 0.02 ) Σ = 2.01 (Ti 0.06 Fe 3+ 0.23 Al 0.17 ) Σ = 1.00 O 4 .

Crystal structure

Qandilite crystallizes cubically in the space group Fd 3 m (space group no. 227) with the lattice parameter a  = 8.40  Å and 8 formula units per unit cell . Template: room group / 227

properties

Qandilit is only partially soluble in cold hydrochloric acid, but completely soluble in hot hydrochloric acid (50%) as well as in hot sulfuric acid (H 2 SO 4 ) and hot nitric acid.

With a Mohs hardness of 7, qandilite is one of the hard minerals that, like the reference mineral quartz , is able to scratch simple window glass. In contrast to most other spinels, qandilite shows perfect cleavage according to the {111} octahedron .

Its magnetic properties are as strong as those of magnetite .

Education and Locations

At its type locality on the Dupezeh in Iraq, qandilite formed in forsterite- rich metamorphic rocks in contact with kersutite-rich banded diorite . In addition to forsterite found here as additional Begleitminerale still calcite , perovskite and spinel .

Qandilite is one of the very rare mineral formations and has so far only been detected in a few samples from less than 10 documented sites. Its type locality Dupezeh is the only known site in Iraq to date .

Across Europe, the mineral found previously only in the municipality of Cusano Mutri belonging bauxite - deposit Regia Piana and the volcanic rocks of the Somma - Vesuvius complex in the Italian region of Campania and in Allt Guibhsachain near Ballachulish in the Scottish Highlands .

Qandilit is still known worldwide from the lamproit fields in the Nalgonda district of the Indian state of Telangana, the precious metal deposits of the Kondjor massif in the Aldan highlands in the Sakha Republic (Yakutia) or the Khabarovsk region in the Russian Federation District Far East and at the Kimberlite 73 site near Hermansville in Menominee County of the US state of Michigan.

See also

literature

  • HM Al-Hermezi: Qandilite, a new spinel end-member, Mg 2 TiO 4 , from Qala-Dizeh region, NE Iraq . In: Mineralogical Magazine . tape 49 , December 1985, pp. 739–744 (English, rruff.info [PDF; 1.9 MB ; accessed on September 17, 2018]).
  • Barry A. Wechsler, Robert B. von Dreele: Structure refinements of Mg 2 TiO 4 , MgTiO 3 and MgTi 2 O 5 by time-of-flight neutron powder diffraction . In: Acta Crystallographica . B45, 1989, p. 542-549 , doi : 10.1107 / S010876818900786X (English).
  • Roberta L. Millard, Ronald C. Peterson, Brian K. Hunter: Study of the cubic to tetragonal transition in Mg 2 TiO 4 and Zn 2 TiO 4 spinels by 17 O MAS NMR and Rietveld refinement of X-ray diffraction data . In: American Mineralogist . tape 80 , 1995, pp. 885–896 (English, rruff.info [PDF; 1.5 MB ; accessed on September 17, 2018]).
  • Hugh St. C. O'Neill, Simon AT Redfern, Sue Kesson, Simine Short: An in situ neutron diffraction study of cation disordering in synthetic qandilite Mg2TiO4 at high temperature . In: American Mineralogist . tape 88 , 2003, p. 860–865 (English, rruff.info [PDF; 186 kB ; accessed on September 17, 2018]).

Web links

Individual evidence

  1. ^ IMA / CNMNC List of Mineral Names; March 2018 (English; PDF 1.65 MB)
  2. ↑ 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 .
  3. ↑ a b c d Qandilite . 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 September 17, 2018]).
  4. ↑ 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.  189 (English).
  5. ↑ Webmineral - Qandilite (English)
  6. ↑ a b c d e f g h i HM Al-Hermezi: Qandilite, a new spinel end-member, Mg 2 TiO 4 , from Qala-Dizeh region, NE Iraq . In: Mineralogical Magazine . tape 49 , December 1985, pp. 739 (English, rruff.info [PDF; 1.9 MB ; accessed on September 17, 2018]).
  7. ^ A b 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. 304 .
  8. ↑ HM Al-Hermezi: Qandilite, a new spinel end-member, Mg 2 TiO 4 , from Qala-Dizeh region, NE Iraq . In: Mineralogical Magazine . tape 49 , December 1985, pp. 744 (English, rruff.info [PDF; 1.9 MB ; accessed on September 17, 2018]).
  9. ↑ Catalog of Type Mineral Specimens - Q. (PDF 14 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed August 29, 2019 .
  10. ↑ 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 [PDF]).
  11. ↑ HM Al-Hermezi: Qandilite, a new spinel end-member, Mg 2 TiO 4 , from Qala-Dizeh region, NE Iraq . In: Mineralogical Magazine . tape 49 , December 1985, pp. 743 (English, rruff.info [PDF; 1.9 MB ; accessed on September 17, 2018]).
  12. ↑ HM Al-Hermezi: Qandilite, a new spinel end-member, Mg 2 TiO 4 , from Qala-Dizeh region, NE Iraq . In: Mineralogical Magazine . tape 49 , December 1985, pp. 741 (English, rruff.info [PDF; 1.9 MB ; accessed on September 17, 2018]).
  13. ↑ List of localities for qandilite in the Mineralienatlas and Mindat