Free life
| Free life | |
|---|---|
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|
| General and classification | |
| chemical formula | PbAgSbS 3 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.JB.15 ( 8th edition : II / E.17) 04/03/06/02 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Room group (no.) | P 2 1 / a (No. 14) |
| Lattice parameters |
a = 7.53 Å ; b = 12.79 Å; c = 5.88 Å β = 92.2 ° |
| Formula units | Z = 4 |
| Twinning | after (100) |
| Physical Properties | |
| Mohs hardness | 2 to 2.5 |
| Density (g / cm 3 ) | 6.2 to 6.3 |
| Cleavage | indistinct |
| Break ; Tenacity | shell-like to uneven |
| colour | lead gray to steel gray, silver white |
| Line color | lead gray to steel gray, silver white |
| transparency | opaque |
| shine | Metallic luster |
Freieslebenite , as Basitomglanz , Donacargyrit , Dark Weißgültigerz or Schilfglaserz known is a rarely occurring mineral from the mineral class of the sulphides and sulfosalts . It crystallizes in the monoclinic crystal system with the chemical composition PbAgSbS 3 and develops prismatic, reed-like, curved crystals that are typical of this mineral, striped parallel to the c-axis, whose color and line color can range from lead gray to steel gray to silver white.
Etymology and history
The mineral was first described in 1783 by Jean-Baptiste Louis Romé de L'Isle , who called it Mine d'antimoine grise tenant argent . In his description, L'Isle concentrated almost exclusively on the morphology of the crystals and their noticeable longitudinal stripes.
Since Johann Carl Freiesleben was apparently not aware of L'Isle's publication, he described the mineral a second time in 1817, focusing primarily on its properties and naming it reed glass ore .
Haidinger gave the mineral its name, Freielebenit, which is still valid today in 1845 .
classification
In the old (8th edition) and the new systematics of minerals (9th edition) according to Strunz , the free life is classified in the sulfosalts department. However, the new system subdivides this department even further, so that the mineral is now in the subdivision “Sulfosalts with PbS as a model and the galena derivatives with lead (Pb)”.
The systematics of minerals according to Dana assigns the free life to the division of "sulfosalts with the general chemical composition z / y> 3 - (A + ) i (A 2+ ) j [By Cz], A = metals, B = semi-metals, C = non-metals "
Education and Locations
Free life can be found in the Himmelsfürst mine near Freiberg in Saxony , Felsöbanya in Hungary and Hiendelaencina in Spain . It forms hydrothermally.
Crystal structure
Free life crystallizes monoclinically in the space group P 2 1 / a (space group no. 14) with the lattice parameters a = 7.53 Å ; b = 12.79 Å, c = 5.88 Å and β = 92.2 ° as well as four formula units per unit cell .
See also
literature
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 58 .
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 477 .
Web links
Individual evidence
- ^ A b c 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. 145 .
- ↑ a b Thomas Witzke : Discovery of free life
- ↑ JC Freiesleben: Description of some of the strange Saxon fossils in my mineral collection, along with historical and geognostic remarks about them. Reed glass ore. (Geognostic work 6), In: Contributions to the mineralogical knowledge of Saxony. Second delivery (1817), pp. 97-101
- ^ W. Haidinger: Handbook of determining mineralogy, containing the terminology, systematics, nomenclature and characteristics of the natural history of the mineral kingdom. Braumüller & Seidel, Vienna 1845, p. 569