Ferrarisite
| Ferrarisite | |
|---|---|
| General and classification | |
| other names |
IMA 1979-020 |
| chemical formula | Ca 5 [(AsO 3 OH) 2 | (AsO 4 ) 2 ] • 9H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.CJ.30 ( 8th edition : VII / C.24) 02.39.03.01 |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triclinic pinacoidal; 1 |
| Space group | P 1 (No. 2) |
| Lattice parameters |
a = 8.29 Å ; b = 6.72 Å; c = 11.20 Å, α = 106.2 °; β = 92.9 °; γ = 99.2 ° |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | not defined |
| Density (g / cm 3 ) | measured: 2.63; calculated: 2.594 |
| Cleavage | completely after {001} |
| Break ; Tenacity | brittle |
| colour | colorless to white |
| Line color | White |
| transparency | transparent to translucent |
| shine | weak glass gloss, silk gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.562 n β = 1.572 n γ = 1.585 |
| Birefringence | δ = 0.023 |
| Optical character | biaxial positive |
| Axis angle | 2V = 83 ° (measured); 84 ° (calculated) |
| Other properties | |
| Chemical behavior | Easily soluble in dilute hydrochloric acid |
Ferrarisite is a very rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the triclinic crystal system with the chemical composition Ca 5 [(AsO 3 OH) 2 | (AsO 4 ) 2 ] · 9H 2 O, so it is a complex, water-containing calcium arsenate.
Ferrarisite only develops small, tabular crystals with a pseudo-hexagonal habit up to about 300 micrometers in size with a weak glass luster , which are usually arranged in semi- gloss , radial-ray mineral aggregates . Fresh mineral samples are colorless and transparent. Unprotected in dry air, however, the mineral dehydrates , which means that it loses its crystal water after a while and turns white.
Etymology and history
Ferrarisite was first discovered in the pit "Gabe Gottes" (including poison pit) in the Haut-Rhin department in the French region of Alsace and described in 1980 by Hubert Bari , Francois Permingeat , Roland Pierrot and Kurt Walenta who named the mineral after the Italian mineralogist Giovanni Ferraris (* 1937) in honor of his contributions to the analysis of the crystal structure of many arsenate minerals.
The mineral was previously found in the Anton pit in the Heubach valley near Wittichen in Baden-Württemberg and described by Kurt Walenta in 1973, but without naming the mineral.
classification
In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Ferrarisite belonged to the department of “Hydrous phosphates without foreign anions ”, where together with Guérinite , Haidingerite , Mcnearite , Irhtemite , Phaunouxite , Picropharmakolite , Rauenthalite and Vladimirite the “ Haidingerit Group "with the system no. VII / C.24 formed.
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 Ferrarisite to the category of “phosphates etc. without additional anions; with H 2 O “. However, this is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section “Only with large cations”, where it is the only member of the unnamed group 8.CJ.30 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Ferrarisite to the class of "phosphates, arsenates and vanadates", but there in the category of "hydrous acidic phosphates etc.". Here he is to be found as the only member of the unnamed group 39.02.03 within the subdivision "Hydrous acid phosphates etc., H 2 (AB) 5 (XO 4 ) 4 × x (H 2 O)".
Crystal structure
Ferrarisite crystallizes triclinically in the space group P 1 (space group no. 2) with the lattice parameters a = 8.29 Å ; b = 6.72 Å; c = 11.20 Å; α = 106.2 °; β = 92.9 ° and γ = 99.2 ° and one formula unit per unit cell .
Modifications and varieties
The compound Ca 5 [(AsO 3 OH) 2 | (AsO 4 ) 2 ] · 9H 2 O is dimorphic , so besides the triclinic crystallizing Ferrarisite it also occurs as a monoclinic crystallizing Guérinite .
Education and Locations
Ferrarisit formed secondarily on mine dumps as a low temperature reaction product in arsenic-containing carbonate - gaits . The accompanying minerals include calcite , lollingite , pharmacolite , phaunouxite , picropharmacolite , rauenthalite and sainfeldite .
Previously known localities are in addition to its type localities pit "gift of God" in France and mine "Anton" in Germany among other things still the pit "L'Eguisse" in Duranus in France, the pit "Johann" at Wittichen in Baden-Wuerttemberg, the hard Koppe near Sailauf in Bavaria, the “Wilhelm” mine and the ore field Richelsdorf in Hesse and the “Dörnberg” mine near Ramsbeck in North Rhine-Westphalia in Germany and the “Grand-Praz” mine near Ayer (Val d'Anniviers) in the Swiss canton of Valais (Stand 2013).
See also
literature
- Hubert Bari, Francois Permingeat, Rolland Pierrot, Kurt Walenta: La ferrarisite Ca 5 H 2 (AsO 4 ) 4 9H 2 O, une nouvelle espèce minérale dimorphhe de la guérinite . In: Bulletin de Minéralogie . tape 103 , 1980, pp. 533-540 (French, brief description in English).
- Michael Fleischer, Louis J. Cabri: New Mineral Names . In: American Mineralogist . tape 66 , 1981, pp. 637–639 ( minsocam.org [PDF; 325 kB ]).
Web links
- Mineral Atlas: Ferrarisite (Wiki)
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. 488 .
- ↑ Webmineral - Ferrarisite
- ↑ a b c Ferrarisite . 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; 66 kB ]).
- ↑ a b c d e Mindat - Ferrarisite
- ↑ Mineral Atlas: Ferrarisite
- ↑ Michael Fleischer, Louis J. Cabri: New Mineral Names . In: American Mineralogist . tape 66 , 1981, pp. 637–639 ( minsocam.org [PDF; 325 kB ]).
- ↑ Find location list for Ferrarisite in the Mineralienatlas and Mindat