Bitikleit
| Bitikleit | |
|---|---|
| General and classification | |
| other names |
|
| chemical formula | Ca 3 SbSnAl 3 O 12 |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic hexakisoctahedral; 4 / m 3 2 / m |
| Space group | Ia 3 d (No. 230) |
| Lattice parameters | a = 12.5240 Å |
| Formula units | Z = 8 |
| Frequent crystal faces | Deltoidal icosity tetrahedron {211} |
| Physical Properties | |
| Mohs hardness | Please complete |
| Density (g / cm 3 ) | calculated: 4.505 |
| Cleavage | Please complete |
| colour | colorless to light yellow |
| Line color | White |
| transparency | Please complete |
| shine | Glass gloss |
| radioactivity | very weak due to traces of uranium and thorium |
| Crystal optics | |
| Refractive index | n = 1.851 (calculated) |
The mineral Bitikleit is a very rare oxide from the upper group of the garnet with the idealized composition Ca 3 SbSnAl 3 O 12 . It crystallizes in the cubic crystal system with the structure of garnet. The crystals have a maximum size of 50 μm and are zoned with kimzeyite- rich cores.
Bitikleit has so far only been detected in its type locality , a calcium silicate xenolite from an ignimbrite from Mount Lakargi, Chegem Caldera in the North Caucasian Republic of Kabardino-Balkaria in Russia .
Etymology and history
As early as the 1970s, Sn garnets, including Ca 3 Sb 5+ Sn 4+ Fe 3+ 3 O 12 ( Dzhuluit ), the Fe analog from Bitikleit, were synthesized and investigated.
In nature, Bitikleit- (SnAl) was described by Irina O. Galuskina and co-workers and recognized as a new mineral by the International Mineralogical Association (IMA) in 2009 . It was named after the historical fortress of Bitikle, not far from where it was found. When the Granat supergroup was reorganized in 2013, the mineral was renamed Bitikleit.
classification
The current classification of the International Mineralogical Association (IMA) counts the Bitikleit to the garnet upper group, where together with Dzhuluit , Usturit and Elbrusit it forms the Bitikleit group with 9 positive charges on the tetrahedrally coordinated grid position.
The 9th edition of the Strunz'schen mineral systematics, valid since 2001 , does not list the Bitikleit. Although Bitikleit is not a silicate, like katoite , because of its formation of mixed crystals with silicate garnets, it would be included in the garnet group with the order number 9.AD.25 in the class of "Silicates and Germanates", Division A (island silicates), Subdivision "D . Island silicates without further anions; Cations in octahedral [6] and usually greater coordination ”.
Chemism
Bitikleit is the Al-analog of Dzhuluit and forms complex mixed crystals mainly with Toturite and Dzhuluit. The crystals are often zoned with a kimzeyite-rich core. The measured composition from the type locality is [X] (Ca 3.029 Mn 2+ 0.003 Sr 0.001 ) [Y] (Sb 5+ 1.075 Sn 4+ 0.740 Ti 4+ 0.095 Mg 0.037 Zr 4+ 0.015 Nb 5+ 0.004 Cr 3+ 0.002 U 6+ 0.001 ) [Z] (Al 1.530 Fe 3+ 1.206 Ti 4+ 0.128 Fe 2+ 0.104 Si 0.031 V 5+ 0.001 ). This can be the following as mixed crystal, for. T. hypothetical end links are expressed: 51% Bitikleit (Ca 3 Sb 5+ Sn 4+ Al 3+ 3 O 12 ) with 23% Dzhuluit (Ca 3 Sb 5+ Sn 4+ Fe 3+ 3 O 12 ) according to the exchange reaction
- [Z] Al 3+ = [Z] Fe 3+ ,
9% bitite-conductive (TiFe) (Ca 3 Sb 5+ Ti 4+ Fe 3+ 3 O 12 ) according to the exchange reaction
- [Y] Sn 4+ + [Z] Al 3+ = [Y] Ti 4+ + [Z] Fe 3+ ,
1.5% Usturit (Ca 3 Sb 5+ Zr 4+ Fe 3+ 3 O 12 ) according to the exchange reaction
- [Y] Sn 4+ + [Z] Al 3+ = [Y] Zr 4+ + [Z] Fe 3+
7% Ca 3 Sb 5+ 2 (Fe 2+ , Mg) Fe 3+ 2 O 12 according to the exchange reaction
- [Y] Sn 4+ + [Z] Al 3+ = [Y] Sb 5+ + [Z] (Fe 2+ Mg)
7% Ca 3 Sb 5+ (Mg, Fe 2+ ) Ti 4+ 2 Fe 3+ O 12 according to the exchange reaction
- [Y] Sn 4+ + [Z] 2Al 3+ = [Y] (Fe, Mg) 2+ + [Z] 2Ti 4+
and 1.5% Ca 3 Sb 5+ (Mg, Fe 2+ ) Si 4+ 2 Fe 3+ O 12 according to the exchange reaction
- [Y] Sn 4+ + [Z] 2Al 3+ = [Y] (Fe, Mg) 2+ + [Z] 2Si 4+ .
In addition, Bitikleit forms mixed crystals with toturite Ca 3 Sn 4+ Si 4+ Fe 3+ 2 O 12 :
- [Y] Sb 5+ + [Z] 3Al 3+ = [Y] Sn 4+ + [Z] Si 4+ Fe 3+ 2
Crystal structure
Bitikleit crystallizes with cubic symmetry in Ia 3 d (No. 230) and the lattice parameter a = 12.5240 Å as well as 8 formula units per unit cell .
The structure is that of garnet . Calcium (Ca 2+ ) occupies the dodecahedral X positions surrounded by 8 oxygen, antimony (Sb 5+ ) and tin (Sn 2+ ) the octahedral Y position surrounded by 6 oxygen and the tetrahedral Z position surrounded by 4 oxygen occupied with aluminum (Al 3+ ).
Education and Locations
Bitikleit has so far only been detected in its type locality , a calcium silicate xenolite from an ignimbrite from Mount Lakargi, Chegem Caldera in the North Caucasian Republic of Kabardino-Balkaria in Russia . It formed here at temperatures above 800 ° C and low pressure in the cuspidine - fluorite zone of calcium silicate carrons at the contact with the ignimbrite. Bitikleit occurs here along with Cuspidin, fluorite, wadalite , Rondorfit , Bultfonteinit , Lakargiit , Tazheranit , Toturit , Kimzeyit, As-containing fluorine and Hydroxylellestadit , minerals of Ettringitgruppe , perovskite , Magnesioferrit , Afwillit , hillebrandite and other unidentified Ca hydrosilicates on . It is often encrusted by F-containing hydrogrossular .
See also
Web links
- Mineral Atlas: Bitikleit (Wiki)
- Bitcoin. In: mindat.org. Hudson Institute of Mineralogy, accessed March 28, 2019 .
- American-Mineralogist-Crystal-Structure-Database - Bitikleite. In: rruff.geo.arizona.edu. Accessed March 28, 2019 .
Individual evidence
- ↑ a b c d e f g h i j k l m n o p Irina O. Galuskina, Evgeny V. Galuskin, Thomas Armbruster, Biljana Lazic, Piotr Dzierżanowski, Viktor M. Gazeev, Krystian Prusik, Nikolai N. Pertsev, Antoni Winiarski, Aleksandr E. Zadov, Roman Wrzalik, and Anatoly G. Gurbanov: Bitikleite- (SnAl) and bitikleite- (ZrFe): New garnets from xenoliths of the Upper Chegem volcanic structure, Kabardino-Balkaria, Northern Caucasus, Russia . In: American Mineralogist . tape 95 , no. 7 , 2010, p. 959–967 (English, available online at rruff.info [PDF; 1,4 MB ; accessed on March 28, 2019]).
- ↑ a b List of locations for Bitikleit at the Mineralienatlas and at Mindat
- ↑ AP Dodokin, p Lyubutin, BV Mill, VP Peshkov: Mossbauer Effect in Anti Ferromagnetic Substances With Garnet Structures . In: Soviet Physics JETP . tape 36 , no. 3 , 1973, p. 526–531 (English, available online at jetp.ac.ru [PDF; 200 kB ; accessed on March 28, 2019]).
- ^ A b Edward S. Grew, Andrew J. Locock, Stuart J. Mills, Irina O. Galuskina, Evgeny V. Galuskin and Ulf Hålenius: IMA Report - Nomenclature of the garnet supergroup . In: American Mineralogist . tape 98 , 2013, p. 785–811 ( rruff.info [PDF; 1.1 MB ; accessed on April 28, 2020]).