Dzhuluit
| Dzhuluit | |
|---|---|
| General and classification | |
| other names |
IMA2010-064 |
| chemical formula | Ca 3 SbSnFe 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 = 12.536 (natural) 12.634 (synthetic) Å |
| Formula units | Z = 8 |
| Physical Properties | |
| Mohs hardness | Please complete |
| Density (g / cm 3 ) | calculated: 4.705-4.750 |
| Cleavage | Please complete |
| colour | light yellow to dark brown |
| Line color | cream colored |
| transparency | Please complete |
| shine | Glass gloss |
| radioactivity | weak due to low uranium content |
| magnetism | antiferromagnetic below 40 ° K |
| Crystal optics | |
| Refractive index | n = 1.851 (calculated) |
The mineral Dzhuluit is a very rare oxide from the upper group of garnets with the idealized composition Ca 3 SbSnFe 3 O 12 . It crystallizes in the cubic crystal system with the structure of garnet. The inclusion-rich, yellow to brown crystals have a maximum size of 50 μm.
Dzhuluit has so far only been proven 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 ), were synthesized and investigated for their magnetic properties.
In nature, Dzhuluit was described by Irina O. Galuskina and co-workers and in 2010 it was first recognized as a new mineral by the International Mineralogical Association (IMA) under the name Bitikleit- (SnFe) . It was named after the historical fortress of Bitikle, not far from where it was found. When the garnet supergroup was reorganized in 2013, the mineral was renamed Dzhuluit, after the mountain Dzhulu near the site.
classification
The current classification of the International Mineralogical Association (IMA) counts the Dzhuluit to the garnet upper group, where together with Bitikleit , Usturit and Elbrusit it forms the Bitikleit group with 9 positive charges on the tetrahedral coordinated grid position.
The 9th edition of Strunz's mineral classification , which has been in effect since 2001 , does not list the Dzhuluit. Although Dzhuluit is not a silicate, just like Katoit , it would , because of its formation of mixed crystals with silicate grenades, be placed 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 ”.
Crystal structure
Dzhuluit crystallizes with cubic symmetry in Ia 3 d (No. 230) with 8 formula units per unit cell . The synthetic end member has the lattice parameter a = 12.634 Å , the natural mixed crystal from the type locality a = 12.536 Å.
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 iron (Fe 3+ ).
Chemism
Dzhuluit is the Fe analog of Bitikleit and forms complex mixed crystals mainly with Bitikleit and Elbrusite. The measured composition from the type locality is [X] (Ca 2.954 Fe 2+ 0.043 Mg 0.003 ) [Y] (Sn 4+ 0.850 Sb 5+ 0.764 Zr 4+ 0.121 U 6+ 0.127 Ti 4+ 0.070 Sc 3+ 0.009 Nb 5 + 0.058 Hf 0.001 ) [Z] (Fe 3+ 2.051 Al 0.653 Ti 4+ 0.087 Fe 2+ 0.182 Si 0.028 ).
Education and Locations
Dzhuluit has so far only been proven 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 contact metamorphic in the sanidinite facies at temperatures above 800 ° C and low pressure in calcium silicate cartridges at the contact with the ignimbrite. Dzhuluit occurs here along with Kumtyubeit , Cuspidin , Fluorchegemit , Larnite , fluorite , wadalite , Rondorfit , Hydroxylellestadit , perovskite , Lakargiit , Kerimasit , Elbrusit , Srebrodolskit , Bultfonteinit , minerals of ettringite - group hillebrandite , Afwillit , Tobermorit -like minerals, Hydrocalumit and Hydrogrossular on.
See also
Web links
- Mineral Atlas: Dzhuluit (Wiki)
- Dzhuluite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
Individual evidence
- ↑ a b c d e f g h i j k l m n o p Irina O. Galuskina, Evgeny V. Galuskin, Joachim Kusz; Piotr Dzierżanowski, Krystian Prusik, Viktor M. Gazeev, Nikolai N. Pertsev, Leonid Dubrovinsky: Dzhuluite, Ca3SbSnFe3 + 3O12, a new bitikleite-group garnet from the Upper Chegem Caldera, Northern Caucasus, Kabardino-Balkaria, Russia . In: European Journal of Mineralogy . tape 25 , no. 2 , 2013, p. 231 - 239 ( schweizerbart.de [PDF; 428 kB ; accessed on May 2, 2020]).
- ↑ a b c d e AP Dodokin, S. Lyubutin, BV Mill, VP Peshkov: Mössbauer Effect In Antiferromagnetic Substances With Garnet Structures . In: Soviet Physics JETP . tape 36 , no. 3 , 1973, p. 526-531 ( jetp.ac.ru [PDF; 200 kB ; accessed on May 2, 2020]).
- ↑ a b List of locations for Dzhuluit in the Mineralienatlas and Mindat , accessed on May 2, 2020.
- ^ 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 ( cnmnc.main.jp [PDF; 2,3 MB ; accessed on July 8, 2017]).