Diaphorite
| Diaphorite | |
|---|---|
 |
|
| General and classification | |
| other names |
Lead silver antimonite |
| chemical formula | Pb 2 Ag 3 Sb 3 S 8 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.JB.05 ( 8th edition : II / E.17) 03.05.04.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / a (No. 14, position 3) |
| Lattice parameters |
a = 15.85 Å ; b = 5.90 Å; c = 17.92 Å β = 116.4 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | measured: 6.04; calculated: 6.019 |
| Cleavage | no |
| Break ; Tenacity | slightly scalloped to uneven; brittle |
| colour | steel gray |
| Line color | steel gray |
| transparency | opaque |
| shine | Metallic luster |
Diaphorite is a rather rare mineral from the mineral class of "sulfides and sulfosalts". It crystallizes in the monoclinic crystal system with the chemical composition Pb 2 Ag 3 Sb 3 S 8 , therefore consists of lead , silver , antimony and sulfur and belongs to the group of ternary sulfosalts .
Diaphorite is opaque in every form and develops prismatic, parallel to the longitudinal axis striped crystals with a metallic sheen . The mineral has a steel-gray color and line color , but shows a white to grayish reflective color on polished surfaces.
Due to the similarity of names, there is a risk of confusion with the aluminum hydroxide diaspore .
Etymology and history
Diaphorite was first described in 1871 by Victor Leopold Ritter von Zepharovich , who named the mineral after the ancient Greek word διαφορά [diaphorá] for difference or difference . With this name, Zepharovich wanted to indicate the difference between chemically similar free life .
In order to finally get clarity with regard to the crystal system, which has been described several times since the discovery of the free life , Zepharovich analyzed various mineral samples that he received from the University of Vienna and the University of Prague , among others . Since these samples mainly came from the New Hope God's treasure trove near Bräunsdorf (Oberschöna) in Central Saxony (Germany) and Příbram in Central Bohemia (Czech Republic), both sites are considered type localities . During his investigations, Zepharovich discovered the previously unknown mineral diaphorite in addition to the free life. According to his analyzes, these were modifications with the same chemical composition Ag 4 Pb 3 Sb 4 S 11 apart from slight differences , whereby he referred to the rhombic modification as diaphorite and the monoclinic modification as free life.
With his results, however, Zepharovich was only right to the extent that these were two independent minerals. However, due to recent investigations by Erwin Hellner in 1959, the chemical composition and crystal structure had to be corrected to the data Ag 3 Pb 2 Sb 3 S 8 (or crystal-chemically correct Pb 2 Ag 3 Sb 3 S 8 ) and monoclinic.
classification
In the meantime outdated, but still in use 8th edition of the mineral classification by Strunz of Diaphorit belonged to the department of "sulfosalts (S: As, Sb, Bi = x)" where he collaborated with Freieslebenite , Marrit , Owyheeit and Zoubekit the unnamed group II / E.17 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies the diaphorite in the category of “sulfosalts with PbS as a model”. This is further subdivided according to the crystal structure and the metal contained in the compound, so that the mineral according to its composition and structure can be found in the sub-section "Galena derivatives with lead (Pb)", where it is the only member of the unnamed group 2.JB.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the diaphorite to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts". Here he is the only member of the unnamed group 05/03/04 within the subdivision " Sulphosalts with the ratio 2.5 <z / y <3 and the composition (A + ) i (A 2+ ) j [B y C z ] , A = metals, B = semimetals, C = non-metals ”.
Crystal structure
Diaphorite crystallizes monoclinically in the space group P 2 1 / a (space group no. 14, position 3) with the lattice parameters a = 15.85 Å ; b = 5.90 Å; c = 17.92 Å and β = 116.4 ° and 4 formula units per unit cell .
Education and Locations
Diaphorit formed hydrothermally in moderate ore - corridors , where he mostly in paragenesis with galena , Miargyrit , sphalerite , Pyrargyrite , pyrite , but also and other sulphide minerals siderite and quartz occurs.
As a rather rare mineral formation, diaphorite can sometimes be abundant at various sites, but overall it is not very common. So far (as of 2013) around 110 sites are known.
In Germany, in addition to its type locality "New Hope from God Fundgrube" near Bräunsdorf, it was also found in the mine “Old Hope God” near Kleinvoigtsberg and the mine “Beschert Glück” near Zug in the Freiberg district in Saxony, in the mine “Claus-Friedrich” near Sankt Andreasberg in Lower Saxony and the "Friedrich-Christian" mine in Wildschapbachtal near Schapbach in Baden-Württemberg.
In the Czech Republic, in addition to its type locality Příbram, Diaphorit also appeared in the district of Březové Hory and at Malovidy , Kutná Hora ( Kaňk , Poličany) and Jáchymov .
In Austria, among others, the Kreuzeck group (Niedermüller Alp, Plattach) and Rottenstein (municipality of Steinfeld) in Carinthia as well as Straßegg near Gasen , Feistritzwald , Inneres Kaltenegg near Rettenegg and Graschnitzgraben near Sankt Marein in the Mürz Valley ( Fischbacher Alps ) in Styria are where diaphorite was found known.
Other locations include Argentina, Australia, Bolivia, China, France, Georgia, Greece, India, Italy, Japan, Canada, Colombia, Mexico, Norway, Peru, Romania, Russia, Sweden, Slovakia, Spain, South Korea, Tajikistan , Uzbekistan and the United States of America.
See also
literature
- MVR Zepharovich: About Diaphorit and Free Life. In: Meeting reports of the Imperial Academy of Sciences. Volume 63 (1871), pp. 130–156 ( PDF 1.26 MB )
Web links
- Mineral Atlas: Diaphorite (Wiki)
- Mindat - Diaphorite
- Webmineral - Diaphorite
- Database-of-Raman-spectroscopy - Diaphorite
- Thomas Witzke : Discovery of diaphorite. Retrieved December 29, 2013 .
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. 91 .
- ↑ Diaphorite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.9 kB )
- ↑ MVR Zepharovich: About Diaphorit and Free Life. In: Meeting reports of the Imperial Academy of Sciences. Volume 63 (1871), pp. 132–133 ( PDF 1.26 MB ; pp. 4–5)
- ↑ Erwin Hellner : About complexly composed Spießglanze III. On the structure of the diaphorite, Ag 3 Pb 2 Sb 3 S 8 . In: Journal of Crystallography. Volume 110 (1958), pp. 169–174 ( PDF 1.76 MB )
- ↑ Mindat - Number of localities for diaphorite
- ↑ Find location list for diaphorite in the Mineralienatlas and Mindat