Digenite
| Digenite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Cu 9 S 5 or β-Cu 1.8 S |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.BA.05e ( 8th edition : II / B.01) 04/02/07/03 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | ditrigonal-scalenohedral; 3 2 / m |
| Space group | R 3 m (No. 166) |
| Lattice parameters | a = 3.92 Å ; c = 48.00 Å |
| Formula units | Z = 15 |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | measured: 5.546; calculated: 5.706 |
| Cleavage | after {111} (for synthetic crystals) |
| Break ; Tenacity | shell-like |
| colour | blue black |
| Line color | grey black |
| transparency | opaque |
| shine | Metallic luster |
Digenite , outdated also known as α-copper luster or blue isotropic copper luster , is a mineral from the mineral class of " sulfides and sulfosalts ", which can sometimes be abundant in various locations, but is generally not very widespread. It crystallizes in the trigonal crystal system with the chemical composition Cu 9 S 5 or β-Cu 1.8 S and is mostly found in the form of adhesions with other copper sulfides and massive mineral aggregates , but rarely also in the form of trigonal or pseudocubic crystals up to about 3 cm size of blue-black color with gray-black line color .
Digenite is opaque even in thin layers. A strong metallic luster can be seen on the crystal surfaces of fresh samples or on freshly cut or broken surfaces . However, these surfaces turn black after some time in the air and become matt or form a brown, powdery coating.
Etymology and history
Digenite was first discovered near Sangerhausen in Saxony-Anhalt and described in 1844 by August Breithaupt , who named the mineral because of its chemical relationship with chalcosin and covellin after the Greek words δύο [dýo] or its prefix δι- [di-] for two and γένος [genos] for species, genus, sex or strain - put together, therefore, "of two-fold descent" - named.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Digenite belonged to the mineral class of "sulfides and sulfosalts" and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 he formed an independent group together with Anilith , Chalkosin, Djurleit , Geerit , Roxbyit , Spionkopit and Yarrowit .
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 Digenite to the class of "sulfides and sulfosalts" and there in the department of "metal sulfides, M: S> 1: 1 (mainly 2: 1) ”. However, this division 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-division "with copper (Cu), silver (Ag), gold (Au)", where it can be found together with the So far only hypothetically known mineral high-digenite forms the unnamed group 2.BA.05e .
The systematics of minerals according to Dana , which is predominantly used in the English-speaking world , assigns the Digenite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here he is together with Chalkosin, Djurleit, Roxbyit, Anilith, Geerit and Spionkopit in the "Chalkosin group (formula: Cu2-x S)" with the system no. 04/02/07 within the subsection " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 2: 1 ".
Crystal structure
Digenite crystallizes trigonal in the space group R 3 m (space group no. 166) with the lattice parameters a = 3.92 Å and c = 48.00 Å as well as 15 formula units per unit cell .
properties
In front of the soldering tube , Digenite melts by splashing into a brittle ball and using soda you can easily get a copper grain . In nitric acid to dissolve Digenite with separation of sulfur and liquid colors the green.
Education and Locations
Digenit formed by hydrothermal processes in primary or secondary copper - deposits . Accompanying minerals in addition to chalcosine include djurleit , bornite , chalcopyrite and other copper minerals as well as pyrite .
In total, Digenit has so far (as of 2011) been detected at more than 700 sites. In addition to its type locality Sangerhausen, the mineral could also be found in Germany in many places in the Black Forest in Baden-Württemberg; near Hagendorf in the Upper Palatinate Forest and Wölsendorf in the Schwandorf district in Bavaria; at Hohenstein in Hesse; near Mausbach (Stolberg) , Untermaubach and Eiserfeld in North Rhine-Westphalia; near Niederhausen an der Appel , Kruft , Mendig , at Ettringer Bellerberg , Bleialf , Fischbach , Imsbach , Rammelsbach and Obermoschel in Rhineland-Palatinate; near Kastel and Walhausen in Saarland; near Neudorf (Harzgerode) and Mansfeld in Saxony-Anhalt and near Gera , Saalfeld and Schnellbach (Floh-Seligenthal) in Thuringia.
In Austria, the mineral appeared mainly in Carinthia , Lower Austria , Salzburg , Styria and Tyrol .
In Switzerland, Digenit was found at Riniken in the canton of Aargau, Aranno in Ticino and several places in the canton of Graubünden .
Other locations are Egypt , Argentina , Armenia , Australia , Belgium , Bolivia , Brazil , Bulgaria , Chile , China , the Democratic Republic of the Congo , Ecuador , Eritrea , Fiji , Finland , France , Ghana , Greece , Greenland , Haiti , India , Indonesia , Iran , Ireland , Italy , Japan , Canada , Kazakhstan , Luxembourg , Madagascar , Morocco , Mexico , Myanmar , Namibia , New Zealand , Niger , Norway , Panama , Papua New Guinea , Peru , the Philippines , Poland , Portugal , Romania , Russia , Zambia , Sweden , Serbia , Zimbabwe , Slovakia , Slovenia , Spain , South Africa , South Korea , Thailand , Trinidad and Tobago , Czech Republic , Turkey , Hungary , Uzbekistan , the United Kingdom (Great Britain), the United States of America (USA) and Cyprus .
Digenite could also be detected in rock samples from the Mid-Atlantic Ridge , the Central Indian Ridge and the East Pacific Ridge .
See also
literature
- August Breithaupt : Two new minerals containing copper from the order of the shine . In: Poggendorff's annals of physics and chemistry . tape 61 , 1844, pp. 671–675 ( rruff.info [PDF; 175 kB ; accessed on August 14, 2017]).
Web links
- Mineral Atlas: Digenit (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Digenite (English)
- American-Mineralogist-Crystal-Structure-Database - Digenite (English)
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 62 .
- ↑ a b Digenite , in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.6 kB )
- ^ A b Paul Ramdohr , Hugo Strunz : Klockmanns textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, Stuttgart 1978, ISBN 3-432-82986-8 , p. 418 .
- ↑ Stefan Weiß: The large Lapis mineral directory . 5th edition. Christian Weise Verlag, Munich 2008, ISBN 3-921656-17-6 .
- ↑ Mindat - Digenite (English)
- ↑ a b List of sites for Digenit in the Mineralienatlas and Mindat