Tiemannit
| Tiemannit | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | HgSe |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CB.05 ( 8th edition : II / C.01) 08/02/02/04 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic-hexakistrahedral; 4 3 m |
| Space group | F 4 3 m (No. 216) |
| Lattice parameters | a = 6.08 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | positive tetrahedron {111}, negative tetrahedron {1 1 1}, cube {111}, as well as the tris tetrahedron {115} and {113} |
| Twinning | often, with [111] as a twin axis |
| Physical Properties | |
| Mohs hardness | 2.5 |
| Density (g / cm 3 ) | 8.19 to 8.47 |
| Cleavage | no |
| Break ; Tenacity | uneven to shell-like; very brittle |
| colour | lead gray to steel gray, brownish |
| Line color | black |
| transparency | opaque (opaque) |
| shine | Metallic luster |
| radioactivity | not radioactive |
| magnetism | diamagnetic |
| Crystal optics | |
| Birefringence | isotropic |
| Other properties | |
| Chemical behavior | Soluble only in aqua regia , decomposed by chlorine gas |
| Special features | good electrical conductor |
Tiemannite (also selenium mercury ) is a relatively rare mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the cubic crystal system with the chemical composition HgSe and develops predominantly granular to massive aggregates , but also well-developed, idiomorphic, maximum 5 mm crystals of lead-gray to steel-gray or brownish color.
Etymology and history
W. Tiemann, "Hütteneleve auf der Zorge", is considered the discoverer of Tiemannite, who found it in 1828 in an old abandoned mine near Zorge / Harz in what is now Lower Saxony, but mistakenly thought it was genuine selenium. Shortly afterwards, the Brunswick mineralogy professor Marx identified the mineral as a compound of selenium and mercury. It was not until 1855 that the geologist and crystallographer Carl Friedrich Naumann introduced the name Tiemannit in honor of W. Tiemann.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the tiemannite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium = 1: 1", where together with Coloradoite , Hawleyite , Rudashevskyite , Metacinnabarite , Polhemusite , Sphalerite and Stilleit the independent "Sphalerite group" formed.
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 assigns the tiemannite to the class of "sulfides and sulfosalts" and there in the department of "metal sulfides, M: S = 1: 1 (and similar) ”. However, this section is further subdivided according to the predominant metals in the compound, so that the mineral can be found in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag) etc." according to its composition is where, together with Coloradoite, Hawleyite, Metacinnabarite, Polhemusite, Rudashevskyite, Sakuraiite , Sphalerite and Stilleit, the still existing "Sphalerite group" with the system no. 2.CB.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Tiemannite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it is together with Coloradoite, Hawleyite, Metacinnabarite, Rudashevskyite, Sphalerite and Stilleit in the "Sphalerite group" (isometric: F 4 3 m ) with the system no. 02.08.02 within the subsection " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1 ".
Crystal structure
Tiemannite crystallizes in the cubic crystal system in the space group F 4 3 m with the lattice parameter a = 6.08 Å (synthetic: 6.085 Å ) and four formula units per unit cell .
properties
morphology
These crystals represent combinations of the positive tetrahedron {111} (typically matt crystal faces) and the negative tetrahedron {1 1 1} (typically shiny crystal faces), which can have a characteristic parallel stripe [1 1 0].
physical and chemical properties
In the reflected light (bevel), Tiemannit is light gray with a delicate brownish tinge and shows a moderately high reflection behavior (in air). The reflection behavior is greatly reduced in oil; the color changes significantly to brown. Internal reflexes are missing. The mineral is diamagnetic and a good electrical conductor. Tiemannite is not radioactive, but is often found in radioactive minerals such as B. uraninite (pitchblende).
Tiemannite is insoluble in acids and only dissolves in aqua regia.
Modifications and varieties
The variety Lerbachite (also selenium mercury lead gloss), locally named after the Osteroder district Lerbach in the Harz Mountains , consists of a mixture of Clausthalite and Tiemannite. The variety Zorgit , locally named after Zorge in the Harz Mountains, consists of a mixture of Clausthalite, Umangite and some Tiemannite. This mixture was also Raphanosmit , Glasbachit called Selenbleispat or selenium copper galena. Culebrit , named after Culebras in Mexico, refers to a mixture of tiemannite and sphalerite .
Education and Locations
Tiemannite forms hydrothermally and is found mainly on hydrothermal selenium veins. Accompanying minerals are other selenides such as clausthalite , eukairite , naumannite , klockmannite and umangite , sulfides such as metacinnabarite , galena and sphalerite , as well as barite , calcite and uraninite .
The world's best crystals, no more than 3 mm in size, accompanied by quartz, barite and manganese oxides, were found in a vein-shaped occurrence in limestones in the Marysvale District, Piute Co., Utah , USA . Crude ores from this deposit reached a thickness of over one meter in places. Rich stairs came from the Doctor Mine, Mun. Cadereyta , Querétaro , Mexico and from the Virgen de Surumi silver deposit (Pacajake Mine) near Colquechaca , Potosí Department, Bolivia .
The type locality is the St. Lorenz mine, Burgstätter Gangzug, Clausthal-Zellerfeld , Harz . Other sites in Germany are the Weintraube mine near Lerbach and the Brummerjahn mine near Zorge (both Lower Saxony ), the Eskaborner tunnel near Tilkerode and the Grauwackesteinbruch Rieder (both Saxony-Anhalt), Moschellandsberg near Alsenz-Obermoschel ( Rhineland-Palatinate ) and the shaft 366 near Alberoda ( Saxony ).
In Austria Tiemannit is only known from a small quarry near the Judenbauer, northwest of Kirchschlag in the Bucklige Welt . From Switzerland , Nendaz in the Val de Nendaz, Canton Wallis , is also only known to be a site of discovery.
Also from Hope's Nose , Torquay , Devon (England) , from selenium mineralization in uraninite-calcite veins from Předbořice ( Kovářov ) and Černý Důl ( Bohemia ) and Petrovice near Žďár u Blanska ( Moravia , all in the Czech Republic ) and from the Qiongmo gold deposit, Prov. Shaanxi , China .
Further points of discovery are z. B. Argentina , Australia , Belgium , Canada , Poland , Russia , Spain , the United Kingdom ( Scotland ) and several states in the USA .
use
Tiemannite consists of about 72% mercury and about 28% selenium , but is technically insignificant due to its rarity as a raw material for these elements.
See also
literature
- Tiemannite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 57.8 kB )
Web links
Individual evidence
- ↑ a b c d 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. 77, 843 .
- ^ A b Carl Friedrich Naumann : Elements of Mineralogy . 4th edition. Verlag W. Engelmann, Leipzig 1855, p. 425. ( PDF 367.6 kB )
- ↑ a b c d e f Webmineral - Tiemannite
- ^ A b Samuel Lewis Penfield : Crystallized Tiemannite and Metacinnabarite . In: American Journal Science . 1885, XXIX, pp. 449-454.
- ↑ a b c d e Carl Hintze : Handbook of Mineralogy. First volume. First division . 1st edition. Verlag Veit & Co., Leipzig 1904, p. 708.
- ↑ NN Marx: About some strange fossils in Brunswick . In: Schweiggers Journal for Chemistry and Physics . tape 54 . Verlag Hermann Eduard Anton , Halle 1828, p. 223–225 ( available online in the Journal für Chemie und Physik. P. 463 ff. In the Google book search).
- ↑ Paul Ramdohr : The ore minerals and their adhesions . 4th edition. Akademie-Verlag, Berlin 1975, p. 562-563 .
- ^ JG Haditsch, H. Maus: Old mineral names in German literature . Special volume 3 of the Archives for Resource Research in the Eastern Alps (Ed. OM Friedrich). Publishing house Institute for Mineralogy and Geology of the Montanist University, Leoben 1974, 311 pp.
- ↑ Find location list for Tiemannite at the Mineralienatlas and at Mindat
- ↑ Mercury deposits (Wiki)