Romanite
| Romanite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | Fe 2+ Fe 2 3+ [SO 4 ] 4 • 14H 2 O |
|
Mineral class (and possibly department) |
Sulfates (and relatives) |
|
System no. to Strunz and to Dana |
7.CB.75 ( 8th edition : VI / C.11) 07/29/02/01 |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triclinic-pinacoidal 1 |
| Space group | P 1 |
| Lattice parameters |
a = 6.46 Å ; b = 15.31 Å; c = 6.34 Å α = 90.5 °; β = 101.1 °; γ = 85.7 ° |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 3 to 3.5 |
| Density (g / cm 3 ) | measured: 2.174; calculated: 2.173 |
| Cleavage | completely after {010}, almost completely after {001} |
| Break ; Tenacity | uneven |
| colour | yellowish brown to reddish brown |
| Line color | yellow-brown |
| transparency | translucent |
| shine | Glass gloss, fat gloss, resin gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.519 to 1.524 n β = 1.571 to 1.970 n γ = 1.578 to 1.583 |
| Birefringence | δ = 0.059 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 45 to 51 ° |
| Other properties | |
| Chemical behavior | soluble in water, salty taste |
Romanite is a rarely occurring mineral from the mineral class of " sulfates ( and relatives )". It crystallizes in the triclinic crystal system with the chemical composition Fe 2+ Fe 2 3+ [SO 4 ] 4 • 14H 2 O and develops yellowish-brown to reddish-brown, pseudocubic or thick tabular crystals up to about 3 mm in size, mostly in the form of translucent, granular or stalactitic mineral -Aggregates . Individual crystal surfaces have a glassy sheen , whereas aggregates tend to have a greasy or resinous sheen .
Etymology and history
The Romanite was first discovered in the Rammelsberg mine near Goslar in Lower Saxony and described in 1858 by Joseph Grailich (1829–1859), who named the mineral in honor of Friedrich Adolph Roemer (1809–1869).
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the Romanite belonged to the mineral class of "sulfates, selenates, tellurates, chromates, molybdates, wolframates" and there to the department of "hydrous sulfates without foreign anions ", where it belongs together formed a separate group with Lishizhenit and Ransomit .
The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also assigns Romanite to the class of "sulfates (selenates, tellurates, chromates, molybdates and wolframates)" and there in the department of "Sulphates (selenates etc.) without additional anions, with H 2 O". However, this section is further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With only medium-sized cations”, where it only forms the unnamed group 7.CB.75 together with lishizhenite .
The systematics of minerals according to Dana assigns Romanite to the class of "sulfates, chromates, molybdates" and there in the department of "water-containing acids and sulfates". Here it can be found, also together with lishizhenite, in the unnamed group 07/29/02 within the subdivision of " Water-containing acids and sulphates with A (B) 2 (XO 4 ) 4 × x (H 2 O) ".
Education and Locations
Romanite is formed as an early transformation product from pyrite or pyrrhotite , rarely also as a precipitate of volcanic gases. Begleitminerale include alunite , Copiapit , Halotrichit , Kornelit , Melanterite , Rozenite , Siderotil , Szomolnokit and Voltait .
So far (as of 2010), Römerite has been found at around 90 sites worldwide.
In addition to its type locality Rammelsberg in Lower Saxony, the mineral could also be found in Germany in the "Clara Mine" near Oberwolfach in Baden-Württemberg, near Röhrnbach and Pfaffenreuth- Leonberg (Upper Palatinate) in Bavaria, near Friedland in Mecklenburg-Western Pomerania, near Rohdenhaus ( Wülfrath ), in the Ruhr area mines Franz Haniel , Christian Levin , Julia and near Ramsbeck in North Rhine-Westphalia, in the mining company "Willi Agatz" of the SDAG Wismut in Saxony and near Ronneburg in Thuringia.
In Austria, Römerit performed at Ladinger Spitz , near Wollmersdorf ( Drosendorf-Zissersdorf ) and in various regions of Styria .
In Switzerland, the mineral was found on the Lukmanier Pass , in the former municipality of Saint-Luc VS (Forêt du Rochet) and in Martigny (Les Valettes).
Other locations are Argentina , Australia , Bolivia , Canada , Chile , China , France , Greece , Iran , Italy , Japan , Peru , Portugal , Romania , Slovakia , Spain , South Africa , the Czech Republic , Hungary and the United States of America (USA).
Crystal structure
Römerite crystallizes triclinic in the space group with the lattice parameters a = 6.46 Å ; b = 15.31 Å; c = 6.34 Å; α = 90.5 °; β = 101.1 ° and γ = 85.7 ° and one formula unit per unit cell .
See also
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 608 .
Web links
- Mineral Atlas: Römerit (Wiki)
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. 386 .
- ↑ Webmineral - Romerite (English)
- ↑ Handbook of Mineralogy - Römerite (English, PDF 68.3 kB)
- ↑ a b c d Römerite at mindat.org (engl.)
- ↑ LIBRAIRIE ALAIN BRIEUX. Jean-Bernard Gillot. Sciences - Techniques - Médecine ( Memento des Originals of March 22, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (French, PDF 3.4 MB; p. 31)
