Proustite
- Light Rotgültigerz
- Rotbrändigerz
- Rotgolderz
- Rotgülden
- Rotgültig
- Rubin aperture
- Arsenic silver bezel
Proustite, outdated also well known as a light Rotgültigerz, ruby orifice or arsenic silver bezel is a relatively rare occurring mineral from the mineral class of " sulfides and sulfosalts ." It crystallizes in the trigonal crystal system with the composition Ag3 [ ASS3 ], is thus a chemical point of view belonging to the silver sulfosalts Sulfoarsenid.
Proustite usually develops translucent to opaque and often area- rich crystals with short-to langprismatischem, rhombohedral or scalenohedral habit as well as flat or spitzpyramidalen ends. In addition, however, he finds himself in the form of granular to massive mineral aggregates, crusty coatings or dendrites. Visible crystal faces have a diamond-like luster.
Special Features
The color of fresh Proustitproben varies between scarlet and vermilion. Under the influence of light, the mineral with time darkens and becomes almost black. At the same time, " gray " is due to a fine silver plating. From the very similar, also nachdunkelnden Pyrargyrite he can, however, distinguished by its brighter, more vermilion stroke color.
Before the blowpipe melts Proustite on coal to a silver grain, which makes arsenic odor noticeable.
Etymology and history
The term Rotgültig or Rotgültigerz (also Rotgültigertz, according to Mathesius 1562), red Güldig Ertz (after Ercker 1580) and Rothgüldenerz (after Henckel 1754) had been known since the 16th century miners and was the name of rich silver ores with reddish color and strong, blendeartigem gloss used. By Johann Friedrich Henckel also the name Rothgüldenerz has survived since 1754.
Although Abraham Gottlob Werner in 1789 differed between dark and sparse Rotgiltigerz, but the chemist Joseph Louis Proust in 1804 could only be clarified by its chemical analysis shows that the Rotgültigerze of antimony ( Dark, Ag3SbS3 ) and arsenic (light, Ag3AsS3 ) are two distinct minerals.
While the more common dark Rotgültigerz by Ernst Friedrich Glocker the name Pyrargyrite (from Greek πῦρ [PUR ] "Fire" and ἄργυρος [ argyros ] for " silver " ) in 1831, named François Sulpice Beudant 1832 the light Rotgültigerz according to Proust, for whose capacity to understand the situation in order to appreciate the Rotgültigerze.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz Proustite belonged to the mineral class of " sulfides and sulfosalts " and then to the Department of " thio " where he along with Pyrargyrite, Pyrostilpnit, Quadratit, Samsonit and Xanthokon the independent group II/E.07 formed.
The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Proustite also in the class of " sulfides and sulfosalts ," there, however, in the newly defined division of " Sulfoarsenide, Sulfoantimonide, Sulfobismuthide " a. This department is also further divided according to the crystal structure and the possible presence of additional sulfur, so that the mineral is found according to its structure and composition in the subdivision of " island ( Neso ) Sulfarsenide etc. without additional sulfur (S ) " where there is only the unnamed group 2.GA.05 together with Pyrargyrite.
The mainly common in English-speaking classification of minerals according to Dana assigns the Proustite in the class of " sulfides and sulfosalts " and there in the department of " thio " one. Here he is with Pyrargyrite in the " Proustitgruppe " with the system no. 03:04:01 within the subdivision " 03:04 sulfosalts with the ratio 3 > z / y and the composition (A ) i ( A2 ) j [ Bycz ], A = metals, semimetals B =, C = non-metals " to be found.
Education and Locations
Proustite formed primarily from arsenic- rich hydrothermal solutions in cobalt - nickel - and lead-zinc vein deposits. Accompanying minerals can be, among others, native silver, stephanite, rhodochrosite, galena, pyrite, argentite and Pyrargyrite.
As a rather rare mineral formation Proustite at different sites can be abundant in some cases, overall it is not very common. So far (as of 2011) are some 660 localities known as. Known due to exceptional Proustitfunde is especially the silver deposit at Chañarcillo in the small northern Chile, where up to 10 cm long crystals were revealed. The over 12 cm longest, known crystal was, however, 1936 at Schneeberg (Saxony, Germany ) and have been the " Poorman Mine" with banner in Boise County (Idaho, USA ) announced in 1865 finds of crystalline mass with a weight of over 250 kg known.
Other localities lie among others in Argentina, Australia (New South Wales ), Bolivia, Chile, China, Germany (Erzgebirge, resin, Black Forest ), Fiji ( Viti Levu ), France, Greece, Indonesia (Sumatra ), Ireland, Italy (Sardinia ), Japan, Canada ( Ontario ), Kazakhstan, Madagascar, Morocco ( Souss -Massa- Daraâ ), Mexico (Chihuahua, Guanajuato, Guerrero ), New Zealand, Norway, Austria (Carinthia, Salzburg, Tyrol), Peru, Philippines ( Luzon ), Poland ( Lower Silesia), Romania, Russia, Saudi Arabia, Sweden, Switzerland ( Canton of Valais), Slovakia ( Banská Bystrica, Košice ), South Africa, Spain ( Andalusia), Czech Republic ( Bohemia, Moravia ), Hungary ( Borsod- Abaúj- Zemplén ), the United Kingdom (England and Wales) and the United States (Arizona, Colorado, Idaho, Nevada).
Crystal structure
Proustite trigonal crystallized in the space group R3c ( Raumgruppen-Nr. 161) with the lattice parameters a = 10.82 Å and c = 8.69 Å and six formula units per unit cell.
The crystal structure consists of a rhombohedral unit cell whose corners and center are occupied by ASS3 groups. These groups form pyramids with flat Ace as Lace, in the gaps are the Ag atoms, each S atom has two Ag atoms as nearest neighbors.
Use
As a " noble " silver ore ( silver content: 65.41 %) is reduced to silver recovery Proustite.