Teallit
| Teallit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | PbSnS 2 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CD.05 ( 8th edition : II / B.13) 02.09.10.01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | mmm |
| Space group | Pbnm (No. 62, position 3) |
| Lattice parameters |
a = 4.26 Å ; b = 11.41 Å; c = 4.09 Å α = 90 °; β = 90 °; γ = 90 ° |
| Formula units | Z = 2 |
| Twinning | observed only in polished sections |
| Physical Properties | |
| Mohs hardness | 1.5 |
| Density (g / cm 3 ) | calculated: 6.569 measured: 6.36 |
| Cleavage | perfect {100} |
| Break ; Tenacity | irregular |
| colour | silvery gray, lead gray, iron gray |
| Line color | black |
| transparency | opaque (opaque) |
| shine | Metallic luster |
| Crystal optics | |
| Pleochroism | weak; white with a tinge of light gold to pure white |
| Other properties | |
| Special features | Contamination by Fe possible, locally high silver content |
Teallite is a seldom occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical composition PbSnS 2 and therefore chemically a lead - tin sulfide.
Teallite crystallizes in the orthorhombic crystal system and is mostly found in the form of leafy crystal aggregates up to a few centimeters in size. The mineral is in any form opaque ( opaque ) and displays on the surface of the lead-gray grains have a metallic luster , which is frequently starts matt or iridescent. Polished, however, Teallit appears white with a slight yellow tinge.
Etymology and history
Teallit was first described from the Santa Rosa corridor of the mine of the same name in the Monserrat-Antequera mining district near Pazña in the Oruro department in Bolivia . The mineral was named after the geologist and former director general of the Geological Survey of Great Britain and Ireland Sir Jethro Justinian Harris Teall . He had been the holder of the Bigsby Medal since 1889 and also received the Wollaston Medal in 1905 .
classification
In the old systematics of minerals according to Strunz (8th edition) , Teallite was still inaccurately classified in the section "Sulphides with the molar ratio of metal: sulfur, selenium, tellurium = 1: 1", where together with Herzenbergite it was classified within the Herzenbergite range who formed “PbS types and relatives”.
Since the 9th edition of Strunz's mineral systematics, the mineral has belonged to the department of “Metal sulfides, M: S = 1: 1 (and similar)” and there to the subdivision “with tin (Sn), lead (Pb), mercury (Hg ) etc. ". It forms the Herzenbergite group there together with Herzenbergite .
The systematics of minerals according to Dana also assigns the Teallit to the class of sulphides and there as the only member to date in the as yet unnamed "Group 02.09.10 " within the division of "Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1 “a.
Crystal structure
Teallite crystallizes in the orthorhombic crystal system in the space group Pbnm (space group no. 62, position 3) with the lattice parameters a = 4.26, b = 11.41 and c = 4.09 Å as well as two formula units per unit cell .
Education and Locations
Teallite is formed by hydrothermal processes in sulfidic lead and tin-containing ore veins that are bound to orrogens in the area of subduction zones . Accompanying minerals include wurtzite , quartz , cassiterite , Franckeit and arsenopyrite .
As a rare mineral formation, Teallite is not very common. So far (as of 2020) fewer than 40 sites are known to be known. In addition to its type locality , the Santa Rosa mine in the Monserrat-Antequera mining district near Pazña in the Oruro department , the mineral occurred in Bolivia in the Oruro and Potosí departments at 20 other locations. Another two sites are located in the neighboring Argentine Department of Rinconada in the Oploca mine within the Pirquitas silver and tin deposit.
In Europe, the mineral was found in Radvanice v Čechách in the north of the Czech Republic in the local Kateřina coal mine ( Königgrätz region ) as well as in the gold, silver, copper and mercury deposits near the southeast Slovak village of Hnilec ( Kaschau Region ) on the river of the same name and also in the copper mines near the small town of Bălan in the Romanian Harghita district in Transylvania . Furthermore, the inland island of Pahasaari near Savonlinna in the south- eastern Finnish landscape of South Savo is known as a location for teallite within a batholith .
Worldwide, the mineral was also found at several locations in southeast China and in New South Wales, Australia in the Wallah-Wallah silver mine and in Tasmania in the Mount Bischoff mine ( Waratah-Wynyard ). Other sites are the Toyoha mine near Sapporo on the Japanese island of Hokkaidō , the Greenlandic cryolite deposit near Ivigtut in the Kommuneqarfik Sermersooq and the Nenzel Hill in the Rochester mining district, Pershing County in Nevada , United States .
use
Because of its rarity, teallite is of minor importance worldwide as tin and lead ore. In the Carguaicollo mine in the Department of Potosí , Bolivia , however, it is the main ore for tin production.
Today, levels of the mineral are particularly sought after by collectors.
See also
literature
- C. Palache, H. Berman, C. Frondel: The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892. Volume I: Elements, Sulfides, Sulfosalts, Oxides. 7th edition, revised and expanded. John Wiley and Sons, Inc., New York 1944, pp. 439-441.
Web links
- Teallit . In: Mineralienatlas , accessed on April 18, 2020.
- Teallite Mineral Data . In: Mineralogy Database - webmineral.com , accessed April 18, 2020.
Individual evidence
- ↑ a b c d e f g h i Teallite. In: mindat.org . Hudson Institute of Mineralogy, accessed April 18, 2020 .
- ↑ a b Rösler, Hans Jürgen : Textbook of Mineralogy . 3. Edition. VEB German publishing house for basic industry , Leipzig 1984, p. 307 .
- ↑ Carguaicollo mine. In: Mineralienatlas . Retrieved April 18, 2020 .