Tsumebit
| Tsumebit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | Pb 2 Cu [OH | SO 4 | PO 4 ] |
|
Mineral class (and possibly department) |
Phosphates, arsenates, vanadates - anhydrous phosphates with foreign anions |
|
System no. to Strunz and to Dana |
8.BG.05 ( 8th edition : VII / B.24) 04.43.02.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / m (No. 11) |
| Lattice parameters |
a = 8.70 Å ; b = 5.80 Å; c = 7.85 Å β = 111.5 ° |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 3.5 |
| Density (g / cm 3 ) | measured: 6.01 to 6.13; calculated: 6.22 |
| Cleavage | no |
| Break ; Tenacity | uneven, brittle |
| colour | emerald green |
| Line color | green |
| transparency | transparent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.900 n β = 1.920 n γ = 1.942 |
| Birefringence | δ = 0.042 |
| Optical character | biaxial positive |
| Axis angle | 2V = measured and calculated: 90 ° |
| Pleochroism | weak |
Tsumebit is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the monoclinic crystal system with the chemical composition Pb 2 Cu [OH | SO 4 | PO 4 ] and develops predominantly crusty coatings and massive aggregates in an emerald green color.
Etymology and history
Tsumebit was first discovered in the Tsumeb mine in Namibia and described independently at the same time in 1912 by Karl Busz and Vojtěch Rosický . Busz named the mineral after its type of locality , Rosický called it preslite . The name Tsumebit prevailed.
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the tsumebite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates with foreign anions ", where it together with arsenic brackebuschit , arsentsumebit , bearthite , Brackebuschit , Bushmakinit , Calderónit , Feinglosit , Gamagarit , Goedkenit , Jamesit , Lulzacit and Tokyoit the "Brackebuschit group" with the system number. VII / B.24 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns tsumebit to the class of “phosphates, arsenates and vanadates” and there to the department of “phosphates, etc. with additional anions; without H 2 O “. However, this section is further subdivided according to the size of the cations involved and their molar ratio to the phosphate, arsenate or vanadate complex, so that the mineral can be classified in the sub-section “With medium-sized and large cations; (OH, etc.): RO 4 = 0.5 "is to be found, where it together with 1 Arsenbrackebuschit , Arsentsumebit, Bearthit, Brackebuschit, Bushmakinit, Calderónit, Feinglosit, Gamagarit, Goedkenit and Tokyoit the" Brackebuschit group "with the System no. 8.BG.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the tsumebit to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates". Here he is the namesake of the "tsumebit group" with the system no. 43.04.02 and the other member Arsentsumebit can be found in the subsection of " Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen) ".
Crystal structure
Tsumebite crystallizes in the space group P 2 1 / m (space group no. 11) with the lattice parameters a = 8.70 Å ; b = 5.80 Å; c = 7.85 Å and β = 111.5 ° and 2 formula units per unit cell .
Education and Locations
Tsumebite forms as a secondary mineral in oxidation zones Arsenic Lead - copper - deposits . Accompanying minerals include azurite , cerussite , malachite , mimetite , olivite , smithsonite and wulfenite .
As a rare mineral formation, tsumebite could only be detected in a few places, whereby so far (as of 2016) around 30 sites are known. In Germany, the mineral occurred among others at Ühlingen-Birkendorf and Oberwolfach in Baden-Württemberg, at Bensheim and Altenmittlau in Hesse and at Niederfischbach in Rhineland-Palatinate.
Other locations are Broken Hill in Australia, near Diego de Almagro (city) in the Chilean Región de Atacama , Sainte-Marie-aux-Mines and Ébreuil in France, Ozieri in Italy, the Japanese prefecture of Akita , Kipushi in the Democratic Republic of the Congo, Roughton Gill in Cumbria, United Kingdom, and several places in the US states of Arizona , California , Montana , Nevada, and New Mexico .
use
Tsumebite has no economic significance except as a mineral sample.
See also
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 634 .
- K. Busz: Tsumebit, a new lead-copper-phosphate from Otavi, German South-West Africa . In: Festschrift dedicated to the participants of the 84th meeting of German naturalists and doctors in Münster i. Westf. From the Medical and Natural Science Society in Münster (available online at archive.org )
Web links
- Mineral Atlas: Tsumebit (Wiki)
Individual evidence
- ↑ Webmineral - Tsumebite (English)
- ↑ a b c d Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 453 .
- ↑ Tsumebite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 64 kB )
- ↑ a b c d e Mindat - Tsumebite (English)
- ^ Vojtěch Rosický: Preslite, a new mineral from Tsumeb in German South West Africa , 1912
- ↑ Doelter: The elements and compounds of: Ti, Zr, Sn, Th, Nb, Ta, N, P, As, Sb, Bi, V and H , Volume 3, Part 1, p. 446 ( restricted preview in the Google Book Search)
- ↑ Mindat - Number of localities for Tsumebit
- ↑ Find location list for Tsumebit in the Mineralienatlas and in Mindat