Yafsoanite

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Yafsoanite
General and classification
other names

IMA 1981-022

chemical formula Ca 3 Te 2 6+ Zn 3 O 12
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.CC.25 ( 8th edition : 4 / K.15)
02/07/14/01
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Ia 3 d (No. 230)Template: room group / 230
Lattice parameters a  = 12.635  Å
Formula units Z  = 8
Frequent crystal faces Rhombic dodecahedron {110}, cube {100}, octahedron {111}
Physical Properties
Mohs hardness 5.5
Density (g / cm 3 ) calculated: 5.441
Cleavage no
colour light to dark brown
Line color Please complete!
transparency translucent
shine Glass gloss
Crystal optics
Refractive index n  = 1,800
Birefringence δ = -
Other properties
Chemical behavior soluble in acids, no reaction with KOH and FeCl 2 solutions

The mineral yafsoanite is a very rare oxide from the upper group of garnets with the composition Ca 3 Te 2 6+ Zn 3 O 12 . It crystallizes in the cubic crystal system with the structure of garnet and forms rhombic dodecahedral crystals or radial aggregates of less than a millimeter in size.

The crystals are transparent with a glass luster and with a light to dark brown color.

Etymology and history

Yafsoanite was discovered in a gold deposit near Aldan in southern Yakutia , Siberia , and recognized as a new mineral by the IMA in 1982. The explorers Kim, NV Zayakina and Yu. G. Lavrent'yev named the new mineral after the Yakut branch of the Siberian section of the Russian Academy of Sciences , or YaFSOAN for short.

Seven years later, Jarosch and Zemann re-examined the structure of yafsoanite. They recognized that yafsoanite is structurally of the garnet type and gave the formula in its current form.

classification

The current classification of the International Mineralogical Association (IMA) counts the yafsoanite in the garnet upper group, where so far (2013) it is the only mineral with 6 positive charges (Zn 3 ) on the tetrahedral coordinated lattice position.

In the 8th edition of the mineral systematics according to Strunz , which is now outdated but still in use , yafsoanite belonged to the mineral class of "oxides and hydroxides", where together with Cuzticit , Frankhawthorneit , Jensenit , Khinit , Kuranakhit , Leisingit , Mcalpineit , Montanit , Parakhinit , Utahit , Xocomecatlit the group of tellurates with [Te 6+ O 6 ] 6− groups and related structures with the system no. IV / K.15 .

The 9th edition of Strunz's mineral systematics, valid since 2001, also assigns yafsoanite to the class of "oxides (hydroxides, V [5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)". There, according to its composition and structure, it is classified in section C (metal: oxygen = 2: 3, 3: 5 and comparable) in sub-section C. (with large and medium-sized cations) as a single mineral with system no. 4.CC.25 led.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the yafsoanite to the class of "oxides and hydroxides" and there in the "multiple oxides" section. Here he is to be found as the only member of the unnamed group 02/07/14 within the subsection “Multiple Oxides (A + B 2+ ) 2 X 4 , Spinel Group ”.

Crystal structure

Yafsoanite crystallizes with cubic symmetry in the space group Ia 3 d (space group no. 230) and the lattice parameter a  = 12.635  Å as well as 8 formula units per unit cell . Template: room group / 230

The structure is that of garnet . Calcium (Ca 2+ ) occupies the dodecahedral X position surrounded by 8 oxygen, tellurium (Te 6+ ) the octahedral Y position surrounded by 6 oxygen and zinc (Zn 2+ ) the tetrahedral Z position surrounded by 4 oxygen.

Education and Locations

Yafsoanite is formed in the metasomatosis of limestone by solutions containing tellurium . At its type locality , the Kuranakh gold deposit near Aldan in the Sakha (Yakutia) Republic , Siberia , Russia , it was found in the form of small grains between calcite crystals. It occurs here together with gold , tiemannite , naumannite , clausthalite , altaite , cinnabarite , orpiment , kuranakhite , cheremnykhite , dugganite , descloicite and Te-Pb-Mn- saponite .

Furthermore, so far (as of 2017) the mineral could only be found in the Empire mine, Tombstone in Cochise County , Arizona , USA , on Otto Mountain near Baker (California) in San Bernardino County in California , USA, and in the Moctezuma (Bambolla ) mine, 12 km south of Moctezuma in Sonora , Mexico .

use

Due to its rarity, natural yafsoanite is of no importance as a raw material or gemstone.

Synthetic europium (Eu) -doped yafsoanite shows strong, red luminescence under UV light and can be used for red LEDs.

See also

Web links

Individual evidence

  1. ↑ a b c d e f D. Jarosch, J. Zemann: Yafsoanite: a garnet type calcium-tellurium (VI) -zinc oxide . In: Mineralogy and Petrology . tape 40 , no. 2 , May 1989, pp. 111-116 , doi : 10.1007 / BF01164321 .
  2. ↑ a b c d e f Stuart J. Mills, Anthony R. Kampf, Uwe Kolitsch, Robert M. Housley, and Mati Raudrepp: The crystal chemistry and crystal structure of kuksite, Pb3Zn3Te6 + P2O14, and a note on the crystal structure of yafsoanite, (Ca, Pb) 3 Zn (TeO 6 ) 2 . In: American Mineralogist . tape 95 , 2010, p. 933-938 ( (PDF 2.7MB) ).
  3. ↑ a b c d e f g h i j AA Kim, NV Zayakina and Yu. G. Lavrent'yev: Yafsoanite, (Zn1.38Ca1.36Pb0.26) 3 TeO6, a new tellurium mineral . In: International Geology Review . tape 24 , no. 11 , 1982, pp. 1295-1298 , doi : 10.1080 / 00206818209451072 .
  4. ↑ a b Yafsoanite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 72 kB )
  5. ↑ Find location list for yafsoanite at the Mineralienatlas and at Mindat
  6. ↑ Suyin Zhanga, Yanlin Huanga, Liang Shib, Xuebin Qiaob, Hyo Jin Seo: Synthesis, luminescence and crystallographic structure of Eu3 + -doped garnet-type yafsoanite Ca 3 Te 2 (ZnO 4 ) 3 . In: Physica B: Condensed Matter . tape 404 , no. 21 , November 15, 2009, p. 4136-4141 , doi : 10.1016 / j.physb.2009.07.179 .