Coloradoite
| Coloradoite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Hg Te |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CB.05a ( 8th edition : II / C.01) 08/02/02/05 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic-hexakistrahedral; 4 3 m |
| Space group | F 4 3 m (No. 216) |
| Lattice parameters | a = 6.45 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2.5 ( VHN 100 = 25-28) |
| Density (g / cm 3 ) | measured: 8.10; calculated: 8.092 |
| Cleavage | no |
| Break ; Tenacity | uneven to slightly scalloped; brittle and fragile |
| colour | dark gray to black |
| Line color | black |
| transparency | opaque (opaque) |
| shine | Metallic luster |
| Other properties | |
| Chemical behavior | soluble in nitric acid |
Coloradoite (also Tellurquecksilber ) is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical composition HgTe, that consists of mercury and tellurium in the molar ratio 1: 1, making it chemically speaking mercury telluride , which increases due to the chemical affinity the sulfides is counted.
Coloradoite crystallizes in the cubic crystal system , but has so far only been found in the form of granular to massive and crumbly mineral aggregates . The mineral is opaque in every form and shows a metallic sheen on the surfaces of the dark gray to black aggregates . Occasionally the color can take on a very faint tinge of purple. Coloradoite is also often found with purple, blue and green tarnishing colors. The line color of the mineral, on the other hand, is always black.
Etymology and history
The first description was made at a meeting of the American Philosophical Society in October 1876, the minutes of which were published in 1877. Friedrich August Genth reported there on his discovery of a new mercury telluride mineral called Coloradoite from Keystone Lode, Magnolia District, Colorado. A detailed description followed a year later, during which Genth presented not only Coloradoite but also the discoveries of native tellurium, hessite , calaverite , tellurite , ferrotellurite , roscoelite , volborthite and the likewise new mineral magnolite .
The type localities for Coloradoite have now been specified to the effect that the mineral was discovered in some ore samples from the "Keystone Mine" in the Magnolia District, which WH Wenrich from Denver had made available for the investigation. Further ore samples with coloradorite were discovered around the same time in the nearby "Mountain Lion Mine" and in the "Smuggler Mine" in the Balarat District. All of the pits are located in Boulder County , Colorado . The mineral was consequently named by Genth after its main occurrence in Colorado.
Type material for Coloradorit is not defined.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Coloradoite belonged to the mineral class of "sulfides and sulfosalts (including selenides, tellurides, arsenides, antimonides, bismuthides, sulfarsenides, sulfantimonides and sulfbismutides)" and there to the department of " Sulphides with the molar ratio of metal: sulfur, selenium, tellurium = 1: 1 ”, where together with hawleyite , metacinnabarite , polhemusite , rudashevskyite , sphalerite , stilleit and tiemannite the“ sphalerite group ”with the system no. II / C.01 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 classifies Coloradoite in the category of "Metal sulfides, M: S = 1: 1 (and similar)". However, this is further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag), etc." where, together with hawleyite, metacinnabarite, polhemusite, rudashevskyite, sphalerite, stilleit and tiemannite, the "sphalerite group" with the system no. 2.CB.05a forms.
The systematics of minerals according to Dana also assigns Coloradoite to the class of "sulfides and sulfosalts" and there into the department of "sulfide minerals". Here it is together with sphalerite, stilleit, metacinnabarite, tiemannite, hawleyite and rudashevskyite 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 ".
Chemism
The theoretical, i.e. idealized, composition of Coloradoite (HgTe) contains 61.14% mercury and 38.86% tellurium.
properties
When heated in a tube, coloradoite breaks down and melts easily. The subsequently abundant sublimate contains metallic mercury and tellurium as well as drops of tellurium oxide. When heated on charcoal, coloradoite turns the flame of the soldering tube a greenish flame and a white sublimate is created. The mineral is soluble in nitric acid .
Crystal structure
Coloradoite crystallizes cubically in the zinc blende structure , i.e. in the space group F 4 3 m (space group no. 216) with the lattice parameter a = 6.45 Å and 4 formula units per unit cell .
The crystal structure of Coloradoite consists of a framework of corner-linked mercury tetrahedra with the tellurium atoms in the center. Four of these tetrahedra form a unit cell, which can also be described as a face-centered cubic space lattice (Bravais lattice) made of mercury atoms, which is expanded by embedded tellurium atoms.
Modifications and varieties
No varieties have been known in the literal sense of the word, but two mineral mixtures have been given individual names:
- Coolgardite is a mixture of Coloradoite and various Au-Ag tellurides , which was named after its location in the area around Coolgardie .
- A mixture of Coloradoite and Petzite was given the name Kalgoorlite based on its location in the area around Kalgoorlie-Boulder .
Education and Locations
Coloradoite formed by hydrothermal processes in tellurium precious metal - wires . As Begleitminerale occur among other altaite , Calaverit , chalcopyrite , galena , native gold , krennerite , petzite, pyrite , pyrrhotite , sphalerite , tetrahedrite and Tennantit on.
As a rather rare mineral formation, Coloradoite can in part be abundant at various locations, but overall it is not very common. So far (as of 2018) around 160 sites have been documented worldwide. In addition to its main occurrence in Colorado, the mineral was also found in the USA in the Miller-Newman Mine in the Matanuska-Susitna Borough of Alaska, the Trixie Mine in Utah County of Utah, the Cornucopia Mine in Baker County of Oregon and in several locations in California , Montana , Nevada, and North Carolina .
In Austria, Coloradoite has so far only been found on the northeast face of the Ritterkopf and in the Annastollen near Mitterberg in the municipality of Mühlbach am Hochkönig in Salzburg and on the Valschavielkopf or Iron Gate in the municipality of Silbertal in Vorarlberg.
In Switzerland, the mineral could only be found in the Lengenbach mine near the village of Fäld ( Imfeld ) in the Binn valley and in the Massa gorge near Bitsch in the canton of Valais.
The Czech gold mining district Jílové u Držkova , where individual, millimeter-sized grains were discovered, was also known for its Coloradoite finds .
Other sites are in Armenia, in Australia especially in the mining area around Kalgoorlie-Boulder , Burkina Faso, Chile, China, on the Fiji island of Viti Levu , in Finland, France, Ghana, Greece, Guyana, India, Iran, Italy , Japan, Canada, Kazakhstan, Mexico, New Zealand, Papua New Guinea, the Philippine island of Luzon , Romania, Russia, Zimbabwe, South Africa, Sweden, Tajikistan, the Czech Republic, Hungary and Uzbekistan.
See also
literature
- FA Genth: Stated meeting, October 20th, 1876 . In: Proceedings of the American Philosophical Society . tape 16 , 1877, pp. 287–289 ( rruff.info [PDF; 1.6 MB ; accessed on August 2, 2018]).
- FA Genth: On some tellurium and vanadium minerals. 3. Coloradoite, a new mineral . In: Proceedings of the American Philosophical Society . tape 17 , 1878, p. 113–123 ( rruff.info [PDF; 713 kB ; accessed on August 2, 2018]).
- WF deJong: The structure of the tiemannite and kolodradoite . In: Journal of Crystallography . tape 63 , 1926, pp. 466–472 ( rruff.info [PDF; 537 kB ; accessed on August 2, 2018]).
Web links
- Mineral Atlas: Coloradoite (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Coloradoite (English)
- American-Mineralogist-Crystal-Structure-Database - Coloradoite (English)
Individual evidence
- ↑ WF deJong: The structure of the Tiemannite and Kolodradoit . In: Journal of Crystallography . tape 63 , 1926, pp. 466–472 ( rruff.info [PDF; 537 kB ; accessed on August 2, 2018]).
- ↑ a b Webmineral - Coloradoite (English)
- ^ 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. 77 (English).
- ↑ a b c d e Coloradoite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 60 kB ; accessed on August 2, 2018]).
- ↑ a b c Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 70 .
- ↑ a b FA Genth: On some tellurium and vanadium minerals. 3. Coloradoite, a new mineral . In: Proceedings of the American Philosophical Society . tape 17 , 1878, p. 116 ( rruff.info [PDF; 713 kB ; accessed on August 2, 2018]).
- ^ Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 154 .
- ↑ Mindat - Number of localities for Coloradoite (English)
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (= Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 27 .
- ↑ Find location list for Coloradoite at the Mineralienatlas and at Mindat