Eulytin
| Eulytin | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Bi 4 [SiO 4 ] 3 |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.AD.40 ( 8th edition : VIII / A.12) 05.51.04.01 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic-hexakistrahedral; 4 3 m |
| Space group | I 4 3 d (No. 220) |
| Lattice parameters | a = 10.30 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | Cube {100}, tetrahedron {111}, rhombic dodecahedron {110}, tristedrahedron {211}, {2 1 1} |
| Twinning | (multiple) penetration twins according to (100) |
| Physical Properties | |
| Mohs hardness | 5.5 - 6 |
| Density (g / cm 3 ) | 6.62 - 6.76 (measured), 6.76 (calculated) |
| Cleavage | very imperfect after {110} |
| Break ; Tenacity | shell-like to uneven; brittle |
| colour | dark brown, yellowish gray, gray white, straw yellow, colorless (in thin sections colorless to pale brown), black |
| Line color | white to yellowish gray |
| transparency | transparent to opaque |
| shine | Resin to diamond gloss |
| Crystal optics | |
| Refractive indices | n α = 2.05 |
| Optical character | isotropic, but abnormally uniaxial negative |
| Other properties | |
| Chemical behavior | Easily melted in front of the soldering tube, easily soluble in hydrochloric acid |
Eulytin is a rarely occurring mineral from the mineral class of " silicates " with the chemical formula Bi 4 [SiO 4 ] 3 . Chemically speaking, eulytin is therefore a bismuth (III) silicate .
The mineral crystallizes in the cubic crystal system and develops isometric crystals up to 2 mm in size, the supporting shape of which is the tetrahedron or a tristrahedron . Also widespread are concentric-fibrous, spherical aggregates , which were previously called Agricolit .
Etymology and history
The history of the discovery of eulytin is somewhat complicated because the mineral was described three times under different names by August Breithaupt at the beginning of the 19th century within a few years.
The first description was made by Breithaupt as eulytin in the form of grown balls with a shiny surface. A second description was made under the name bismuth blende , in which Breithaupt stated that he had known the mineral for years, but had always taken it to be sphalerite. Until 1826 he had of Obereinfahrer Scheidhauer in Schneeberg material with crystals from the "Neuglücker Stollnort of Kalbe Fdgr. near Schneeberg im Erzgebirge ”, which“ appeared with quartz, bismuth killer, rarely accompanied by solid bismuth ”and enabled mineralogical characterization. Even longer (since around 1819), Breithaupt had known an occurrence of bismuth blende with "cobalt bloom on a mixture of cobalt gravel, quartz and bismuth" from the mine company near Schneeberg.
Breithaupt carried out a third description in Abraham Gottlob Werner's last mineral system under the name arsenic-bismuth :
“As a result of the arsenic-bismuth, an interesting new genus has grown into the bismuth genus, which is not yet known, but which also seems to be a mineral rarity. It is characterized by the following characteristics: dark hair-brown in color, broken in shape and in small spheres and hemispheres grown up. Externally matte and partly with a wisdom overlay; internally not very shiny to strongly shimmering, of a kind of fat sheen. The break is indistinctly fibrous, tufted and star-shaped, running apart, but also runs into the dense, uneven surface. It might jump into splintery and wedge-shaped fragments; shows a clear predisposition to very thin and concentrically crooked, separate pieces, generally to the structure of the glass head; is soft, somewhat brittle, probably easy to break and heavy.
The arsenic-bismuth has quite a similar external appearance to the fibrous brown cover (shell cover), but is always very different from it, in terms of color, softness, etc. […] The most beautiful changes are, breaking with quartz and chert, from Neuglück to Schneeberg, others from Adam Heber himself. B. "
Strictly speaking, the above quotation represents the first description of the Eulytin, the name on the one hand and the description on the other hand coming from two different sections of the same publication. The name Eulytin, which comes from Breithaupt, refers to the Greek word εύλυτος [eulytos] for "easily meltable" and aims to ensure that the mineral melts "extremely quickly into a rather translucent glass bead" in front of the soldering tube .
The type locality for the mineral is the Neuglücker Stollnort in the Kalbe Fundgrube, Schneeberg, Erzgebirge, Saxony. According to the Type Mineral Catalog Germany, type material does not exist, but according to information in the Handbook of Mineralogy, it should be stored in the Mineralogical Institute of the Technical University of Bergakademie Freiberg in Germany under No. 80824.
Shortly after his description of Wismuthblende Breithaupt had the identity of the three minerals Eulytin , Wismuthblende and arsenic-bismuth recognized. Later, Friedrich August Frenzel which called into question. He took a mineral found in Johanngeorgenstadt in the form of small spheres or hemispheres with a radial fibrous structure or concentric fibrous aggregates as a monoclinic polymorph of eulytin and described it as a new mineral agricolite . It was only Clifford Frondel who established the final identity between the eulytin, which occurs in crystals, and the agricolite, which forms characteristic aggregates.
classification
In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the eulytin belonged to the mineral class of "silicates and germanates" and there to the department of "island silicates (nesosilicates)" where it was the only member of the unnamed group VIII / A.12 forms.
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, also assigns eulytin to the class of "silicates and germanates" and there in the "island silicates (nesosilicates)" category. In the meantime, however, this division has been subdivided more precisely according to the presence of further anions and the coordination of the cations , so that the mineral, according to its crystal-chemical structure, is classified in the sub-division of “island silicates without additional anions; Cations in octahedral [6] and usually larger coordination “is to be found, where it is the only member of the unnamed group 9.AD.40 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns eulytin to the class of "silicates and Germanates" and there in the section of "island silicates". Here he is the only member of the unnamed group 51.05.04 within the subdivision Island Silicates : SiO 4 groups only with cations in> [6] coordination .
Crystal structure
Eulytin crystallizes in the cubic crystal system in the space group I 4 3 d (space group no. 220) , with the lattice parameters a = 10.30 Å and four formula units per unit cell .
The crystal structure of Eulytin consisting of BiO 3 pyramids with Bi at the top of the pyramid, as well as isolated SiO 4 - tetrahedra , which form a connected framework shared corners. Bi is also coordinated by 3 + 3 O atoms at greater distances. No natural mineral is known to be isostructural with eulytin. On the other hand, some synthetic compounds such as B. Bismuth germanate Bi 4 (GeO 4 ) 3 .
properties
morphology
In Schneeberg, Eulytin forms up to 2 mm large, due to the predominance of {111} tetrahedral or {211} tristrahedral crystals, the edges of which can appear rounded due to the large area. The most important surface forms observed on them are the cube {100}, the tetrahedron {111}, the rhombic dodecahedron {110} and the tristrahedron {211} and {2 1 1}. The crystals are either grown individually or come together in spherical groups. (Multiple) penetration twins according to (100) are characteristic. Eulytin from Johanngeorgenstadt, originally referred to as Agricolit, forms small spheres which, when enlarged, dissolve into a group of completely rounded crystals, hemispheres with a radial fibrous structure or concentric fibrous aggregates. Black eulytins from Schneeberg form jet-black spheroids, from the surface of which triangular corners protrude, which correspond to the trist-tetrahedron {211}. These balls reach a diameter of up to 1.2 cm.
physical and chemical properties
The color of the crystals and aggregates of eulytin in Schneeberg is clove brown to reddish brown and wax yellow. The spherical aggregates from Schneeberg are blackish brown and brownish black, but can also be completely black. The color of the spherical aggregates from Johanngeorgenstadt is described as wine yellow, colorless and completely water-light. Eulytin is colorless to pale brown in transmitted light. The line color of the transparent to opaque eulytin, on the other hand, is white to yellowish-gray. The eulytin crystals have a resin-like to diamond-like sheen .
The mineral shows a very imperfect cleavage after the base {110}, but breaks due to its brittleness like glass or quartz , whereby the breaking edges are formed from shell-like to uneven. With a Mohs hardness of 5.5 - 6, eulytin is one of the medium-hard minerals that are slightly easier to scratch with a steel file than the reference mineral orthoclase . The calculated density of the mineral is a maximum of 6.76 g / cm 3 .
Eulytin can be melted very easily (name!) In front of the soldering tube on carbon; it is very easily decomposed in hydrochloric acid .
Modifications and varieties
For a long time the compound Bi 4 [SiO 4 ] 3 was thought to be dimorphic (cubic eulytin, monoclinic agricolite) until both minerals were found to be identical in 1943. Nevertheless, the spherical eulytins with a radial or concentric structure are still called the Agricolit variety today .
Education and Locations
Eulytin is a rare alteration product of primary bismuth minerals and forms secondarily in the oxidation zone of hydrothermal bismuth-containing ore deposits ; it is also known from granite pegmatites .
On the Schneeberger mines, eulytin is associated with bismuthite and quartz and can also be accompanied by solid bismuth , atelestite , pucherite , walpurgin , beyerite , erythrin and nickel skutterudite . Accompanying minerals in the Hechtsberg quarry near Hausach are namibite , chrysocolla and quartz. In other deposits with chalcosine , bismite , clinobisvanite and mrazekite, among others .
Eulytin has only been described as a rare mineral formation from a few sites, but it can be somewhat more common in some localities. So far (as of 2016) around 70 sites are known.
In Schneeberg Eulytin is from the pits “Adam Heber”, “Daniel”, “Society”, “Güldener Falk”, “Hope”, “Young Calf”, “Pucher-Schacht”, “Sauschwart”, “Siebenschlehen”, “Weisser” Hirsch "," Weinstock "and" Weißhäuptel "are known. It also appeared on the pits “United Field” and “Schaarschacht” near Johanngeorgenstadt as well as “Stamm Asser” and “God's destiny” on the Graul near Schwarzenberg (all Erzgebirge , Saxony ). Well-known sites in the Black Forest (Baden-Württemberg) are the "Hechtsberg quarry" near Hausach and the Clara pit in the Rankach valley near Oberwolfach .
From the Wiesbachrinne, Habach Valley , Hohe Tauern , Salzburg , Austria , and the quarries of Iragna , Riviera District , Ticino , Switzerland . From Dognecea near Ocna de Fier (Vaskö), Banat , Caraş-Severin County , Romania . From the pits "Elias", "Adam" and "Rovnost", all Jáchymov , from Horní Slavkov (Schlaggenwald), (all Krušné Hory ) and from Smrkovec (Schönficht), Slavkovský les , Czech Republic . In France from the area Blienschwiller - Dambach-la-Ville, Sélestat , Bas-Rhin , as well as from Heidenbach near Munster and the Brézouard massif near Sainte-Marie-aux-Mines (Markirch), both Haut-Rhin , all Alsace . From the Buckbarrow Beck Veins, Waberthwaite, Southern Fells, Cumbria , England , United Kingdom . From the Sn-W deposit of Syuigachan, Badzhalski Archdistrict, Khabarovsk Region , Far East , Russia .
In the United States , eulytin was found in the Elizabeth R. Mine on Chief Mountain , Pala District in San Diego County and the Blue Bell Mine in Baker, Soda Lake Mts, San Bernardino County , California and the Linka, among others Mine ”in the Spencer Hot Springs District, Lander County , Nevada . From the Evans-Lou mine on Lac Saint-Pierre , Outaouais , Québec , Canada . In Australia , the mineral is known from the Wombat Hole Prospect in Morass Creek Gorge, Benambra, Victoria , and the Biggend Mine in Biggend Shire, Queensland .
Other sites were known from Australia, China, the Czech Republic, France, Germany, Japan, Nepal, Poland, Russia, Spain and Tajikistan.
use
Eulytin with a terminal composition consists of about 84% Bi 2 O 3 and about 16% SiO 2 . Due to its rarity, the mineral is technically completely insignificant as a raw material for bismuth, but it is a coveted mineral for the collector.
See also
literature
- August Breithaupt (1827a): Bismuthblende, a newly determined species of the mineral kingdom. In: Poggendorff's annals of physics and chemistry. Volume 9, pp. 275-281 ( rruff.info PDF; 377 kB).
- Eulytine. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 ( handbookofmineralogy.org PDF; 62 kB).
Web links
- Mineral Atlas: Eulytin (Wiki)
- Mindat - Eulytine
- Webmineral - Eulytine
- Database-of-Raman-spectroscopy - Eulytine
- American-Mineralogist-Crystal-Structure-Database - Eulytine
- Homepage of Thomas Witzke - Eulytin
Individual evidence
- ↑ a b c d e 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. 544 .
- ↑ a b c d e f g h i j k l Eulytine , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 ( handbookofmineralogy.org PDF; 62 kB).
- ^ A b Albin Weisbach : Mineralogical notes: 15. Eulytin . In: New Yearbook for Mineralogy, Geology and Palaeontology . tape 1882 . Swiss beard, Stuttgart 1882, p. 256 .
- ↑ a b c Carl Hintze : Handbook of Mineralogy. Second volume. Silicates and titanates. 1st edition. Verlag Veit & Co., Leipzig 1897, pp. 43-45.
- ↑ a b c Abraham Gottlob Werner , August Breithaupt : Abraham Gottlob Werner's last mineral system. Issued from his estate by order of the Mining Authority and provided with explanations . 1st edition. Craz and Gerlach and Carl Gerold, Freyberg and Vienna 1817, p. 23 and 56–57 ( page preview in Google Book search).
- ↑ a b c August Breithaupt : Bismuthblende, a newly determined species of the mineral kingdom. In: Poggendorff's annals of physics and chemistry. Volume 9, 1827, pp. 275-281 ( rruff.info PDF; 377 kB) - (a).
- ↑ August Breithaupt: Contribution to the knowledge of the bismuth diaphragm, especially with regard to its chemical behavior. In: Yearbook of Chemistry and Physics. Volume 20, 1827, pp. 307-312. - (b).
- ↑ a b c August Frenzel : Mineralogical. 9. Eulytin and Agricolit . In: New Yearbook for Mineralogy, Geology and Palaeontology . tape 1873 . Swiss beard, Stuttgart 1873, p. 791–794 ( Page preview in Google Book Search - a).
- ^ Clifford Frondel : New data on agricolite, bismoclite, koechlinite, and the bismuth arsenates. In: American Mineralogist. Volume 28, 1943, pp. 536-540 ( rruff.info PDF; 297 kB).
- ↑ H. Liu, C. Kuo: Crystal structure of bismuth (III) silicate, Bi 4 (SiO 4 ) 3 . In: Journal of Crystallography. Volume 212, 1997, p. 48.
- ^ August Frenzel: Communications to Professor HB Geinitz. Freiberg November 18, 1873 (About Zeunerit and Agricolit) . In: New Yearbook for Mineralogy, Geology and Palaeontology . tape 1873 . Swiss beard, Stuttgart 1873, p. 947–948 ( page preview in Google Book Search - b).
- ^ August Frenzel: Mineralogical Lexicon for the Kingdom of Saxony . 1st edition. Verlag von Wilhelm Engelmann, Leipzig 1817, p. 2 and 96–97 ( page preview in Google Book Search).
- ↑ a b c Andreas Massanek, Steffen Michalski: From Akanthit to Zeunerit: The minerals of the Schneeberger Revier. In: Lapis. Volume 30, No. 7/8, 2005, pp. 41-66.
- ^ A b c Eugene E. Foord : Clinobisvanite, eulytite, and namibite from the Pala pegmatite district, San Diego Co., California, USA. In: American Mineralogist. Volume 60, 1996, pp. 387-388 ( rruff.info PDF; 112 kB).
- ↑ Mindat - Number of localities for Eulytin
- ^ Fritz Schlegel, Klaus Schumann, Jürgen Siemroth: Finds of heaps of secondary bismuth minerals from Schneeberg in the Erzgebirge. In: Lapis. Vol. 25, No. 2, 1992, pp. 13-33.
- ↑ Find location list for Eulytin in the Mineralienatlas and in Mindat