Baddeleyit
| Baddeleyit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | ZrO 2 |
|
Mineral class (and possibly department) |
Oxides with metal: oxygen = 1: 2 |
|
System no. to Strunz and to Dana |
4.DE.35 ( 8th edition : IV / D.31) 04.04.14.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / c (No. 14) |
| Lattice parameters |
a = 5.151 Å ; b = 5.212 Å; c = 5.317 Å β = 99.23 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 6.5 |
| Density (g / cm 3 ) | 5.5 to 6 |
| Cleavage | {001} clearly |
| Break ; Tenacity | shell-like |
| colour | brown, brownish black, slate gray, colorless, green, yellow, greenish brown |
| Line color | white, brownish white |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 2.13 n β = 2.19 n γ = 2.20 |
| Birefringence | δ = 0.070 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 30 °: calculated: 28 ° |
Baddeleyite is a rather seldom occurring mineral from the mineral class of oxides and hydroxides with a ratio of metal to oxygen = 1: 2. It crystallizes in the monoclinic crystal system with the chemical formula ZrO 2 and is therefore zirconium (IV) oxide from a chemical point of view .
It usually develops tabular crystals of brown-black, green or yellow color and up to 6 cm in size. Colorless crystals are also known. With a Mohs hardness of 6.5, it is one of the medium-hard minerals.
Etymology and history
It was named after Joseph Baddeley , who described the mineral. It was first discovered and described in Sri Lanka and Brazil in 1892 .
The type material is kept in the Natural History Museum in London .
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , baddeleyite belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with a metal: oxygen ratio = 1: 2 (MO 2 and related compounds) “, Where together with calcirtite , cerianite (Ce) , hiärneit , tazheranite , thorianite and uraninite it formed the baddeleyite-uraninite series named after him with the system number IV / D.31 .
The 9th edition of Strunz's mineral systematics , which has been in force since 2001 and is used by the IMA, also classifies baddeleyite in the category of "oxygen = 1: 2 and comparable". However, this is further subdivided according to the size of the cations and the crystal structure, so that the mineral can be classified according to its composition and structure in the sub-section “With medium-sized cations; With various polyhedra ”can be found where it is with Akaogiite (which was only discovered in 2007) in the Baddeleyite group with the system number 4.DE.35 , also named after him .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns baddeleyite to the class of "oxides and hydroxides" and there to the section "oxides" (No. 4) and there to the subgroup "simple oxides with a cation charge of 4" + (AO2) “. Here he can also be found together with Akaogiit of the unnamed group with the system number 04.04.14 .
Crystal structure
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Baddeleyite crystallizes in the monoclinic crystal system in the space group P 2 1 / c (space group no. 14) with the lattice parameters a = 5.151 Å , b = 5.212 Å, c = 5.317 Å and β = 99.23 ° as well as four formula units per unit cell .
Modifications and varieties
Baddeleyite is a modification of zirconium (IV) oxide. Above 1173 ° C it changes into a tetragonal modification , from 2370 ° C into a cubic modification.
Education and Locations
Baddeleyite is often found as weathering gravel in gravel . A total of 191 sites are known.
In Germany , localities are known from Rhineland-Palatinate . On the Laacher See localities are known in Kruft and Mendig . A site is also known in Ettringen . A fourth German site can be found in Wolfstein in the Palatinate .
In Austria there is a place of discovery in Stubenberg am See in Styria . There is also a not precisely localized site in Tyrol .
There are other sites in Algeria , Angola , Antarctica , Argentina , Armenia , the Atlantic Ocean , Australia , Brazil , Burma , Chile , China , Ivory Coast , Finland , France , Gabon , Greenland , India , the Indian Ocean , Iraq , Italy , Japan , Canada , Kazakhstan , the Democratic Republic of the Congo , Madagascar , Morocco , Mexico , Namibia , Norway , Oman , Romania , Russia , Sweden , Sri Lanka , South Africa , Tanzania , the Czech Republic , Uganda , Hungary , Ukraine , the United Kingdom and the U.S. states of Arkansas , California , Colorado , Georgia , Kansas , Minnesota , Montana , New Hampshire , New Mexico , Pennsylvania , Texas , Wisconsin, and Wyoming .
Baddeleyite was also found on the moon together with spinel , chromite , zircon and (OH) -free apatite as a secondary mixture .
use
Baddeleyite is an important raw material for the extraction of zirconium .
See also
literature
- Stefan Weiß: The large Lapis mineral directory . 4th edition. Christian Weise Verlag, Munich 2002, ISBN 3-921656-17-6
Web links
- Mineral Atlas: Baddeleyite (Wiki)
- Webmineral - Baddeleyite
- Database of Raman spectroscopy - Baddeleyite (database, contains further literature)
- American Mineralogist Crystal Structure Database - Baddeleyite (crystal structure database )
Individual evidence
- ↑ a b c d e f g Baddeleyite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy . Mineralogical Society of America, 2001 ( PDF ).
- ↑ a b c d MinDat - Baddeleyite (English)
- ↑ Martin Okrusch, Siegfried Matthes: Mineralogie . 7th edition. Springer Verlag, Berlin 2005, ISBN 3-540-23812-3 , p. 429