Love mountainite
| Love mountainite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Ni 2 [SiO 4 ] |
|
Mineral class (and possibly department) |
Silicates and germanates - island silicates (nesosilicates) |
|
System no. to Strunz and to Dana |
9.AC.05 ( 8th edition : VIII / A.04) 03/01/01/04 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pbnm (No. 62, position 3) |
| Lattice parameters | a = 4.73 Å ; b = 10.19 Å; c = 5.95 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 6 to 6.5 |
| Density (g / cm 3 ) | measured and calculated: 4.6 |
| Cleavage | indistinct after {010} and {100} |
| colour | olive green to yellowish green; in thin layers colorless to light green |
| Line color | White |
| transparency | transparent to translucent |
| shine | Please complete |
| Crystal optics | |
| Refractive indices |
n α = 1.820 n β = 1.854 n γ = 1.888 |
| Birefringence | δ = 0.068 |
| Optical character | biaxial negative |
| Axis angle | 2V = 80 ° (measured); 88 ° (calculated) |
| Pleochroism | X = Y = colorless to light green; Z = greenish yellow |
Liebenbergite is a very rare mineral from the mineral class of " silicates and germanates " with the idealized chemical composition Ni 2 [SiO 4 ] and is therefore chemically a dinickel orthosilicate . Structurally, Liebenbergit is one of the island silicates (nesosilicates).
The mineral crystallizes in the orthorhombic crystal system and is found exclusively in the form of yellowish green, granular mineral aggregates to about one millimeter in diameter or as a joint filling between Trevorit grains. The clear to translucent crystals are typically olive green to yellowish green in color. In thin layers, Liebengergit can also be colorless to light green. His line color , however, is always white.
Etymology and history
The Liebenbergite was first discovered in 1973 in the "Scotia Talk Mine" near Bon Accord near Barberton in the South African province of Mpumalanga . The mineral was analyzed and scientifically described by Sybrand A. de Waal and Lewis C. Calk, who named the mineral after William Roland Liebenberg (1919–1988), the deputy general director of the National Institute for Metallurgy of South Africa.
Type material of the mineral is in Canada in the Royal Ontario Museum in Toronto under the catalog no. M33443 and in the USA at Harvard University in Cambridge (Massachusetts) under catalog no. 133404 and in the National Museum of Natural History in Washington DC under catalog no. 132463 kept.
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Liebenbergite belonged to the mineral class of "silicates and germanates" and there to the department of "island silicates (nesosilicates)", where it was found together with fayalite , forsterite , laihunite and tephroit the " Oliving group " with the system no. VIII / A.04 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also classifies the Liebenbergite under the category of "island silicates". However, this is further subdivided according to the possible presence of additional anions and the coordination of the silicate complexes, so that the mineral is classified in the sub-section “Island silicates without additional anions; Cations in octahedral [6] he coordination ”can be found, where together with fayalite, forsterite, glaukochroit , cherry stone , laihunite and tephroit the“ olive group ”with the system no. 9.AC.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Liebenbergite to the class of "silicates and Germanates" and there to the "island silicates" category. Here he is also in the "Oliving group" with the system no. 51.03.01 to be found in the subsection “ Island silicates: SiO4 groups with all cations only in octahedral [6] coordination ”.
Chemism
The idealized formula for Liebenbergit Ni 2 [SiO 4 ], but containing the analyzed by de Waal and Calk samples as foreign admixtures of magnesium , cobalt and iron . The actual formula of the type mineral is therefore given as (Ni 1.25 Mg 0.33 Co 0.05 Fe 0.12 ) Si 0.99 O 4 . Since all cations together make up a percentage by weight of 1.75%, the rounded formula can also be specified with (Ni, Mg, Co, Fe) 2 SiO 4 .
According to a recent study by S. Akimoto, Y. Matsui and Y. Syono from 1976, there is complete solubility between the nickel-rich and the magnesium-rich end member of the oliving group , corresponding to Ni 2 SiO 4 (= Liebenbergite) and Mg 2 SiO 4 (= Forsterite ). Accordingly, the mixed crystal formula is also given as (Ni, Mg) 2 SiO 4 .
Crystal structure
Liebenbergite crystallizes orthorhombically in the space group Pbnm (space group no. 62, position 3) with the lattice parameters a = 4.73 Å ; b = 10.19 Å and c = 5.95 Å as well as four formula units per unit cell .
Education and Locations
Liebenbergite is formed by contact metamorphism in small nickel deposits in the contact zone between quartzite and serpentinized ultramafites at around 730 ° C and a pressure of almost 2 kbar or in nickel-rich meteorites .
In addition to its type locality , the "Scotia Talk Mine" in Mpumalanga, the mineral occurred in South Africa at the Morokweng crater in the northwest province.
In Germany, the mineral could so far only be found in the Kochhütte (August-Bebel-Hütte) near Helbra and at Lichtloch 25 in the Kupfer-Silberhütte "Gottesbelohnung" near Hettstedt in Saxony-Anhalt.
The only other known site is in the Greek region of Attica , where the mineral was discovered on slag heaps near Agios Konstantinos (Kamariza) in the municipality of Lavrio .
See also
literature
- Sybrand A. de Waal, Lewis C. Calk: Nickel Minerals from Barberton, South Africa: VI. Love Bergite, a Nickel Olivine. In: American Mineralogist Volume 58 (1973), pp. 733–735 ( PDF 307 kB )
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 665 .
Web links
- Mineral Atlas: Liebenbergite (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Liebenbergite
- American Mineralogist Crystal Structure Database - Liebenbergite
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 538 .
- ↑ Webmineral - Liebenbergite (English)
- ↑ a b c d e f Liebenbergite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 71 kB )
- ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
- ↑ a b c d e Mindat - Liebenbergite (English)
- ^ Sybrand A. de Waal, Lewis C. Calk: Nickel Minerals from Barberton, South Africa: VI. Love Bergite, a Nickel Olivine. In: American Mineralogist Volume 58 (1973), p. 734 ( PDF 307 kB )
- ^ IMA / CNMNC List of Mineral Names; 2009 (English, PDF 1.8 MB)
- ↑ MINER Database by Jacques Lapaire - Minéraux et étymologie ( Memento of the original of July 25, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (French)
- ↑ Hans Annersten, gates Ericsson. Anestis Filippidis: Cation ordering in Ni-Fe olivines In: American Mineralogist Volume 67, 1982, pp. 1212–1217 ( PDF 517.2 kB )
- ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 802 .
- ↑ Find location list for Liebenbergite in the Mineralienatlas and Mindat
