Dietrichit
| Dietrichit | |
|---|---|
 |
|
| General and classification | |
| other names |
Zinc alum (obsolete) |
| chemical formula | ZnAl 2 [SO 4 ] 4 • 22H 2 O |
|
Mineral class (and possibly department) |
Sulphates and relatives (see classification ) |
|
System no. to Strunz and to Dana |
7.CB.85 ( 8th edition : VI / C.12) 29.07.03.04 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Room group (no.) | P 2 1 / a (No. 14) |
| Lattice parameters |
a = 21.38 Å ; b = 24.43 Å; c = 6.24 Å β = 100.1 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2 |
| Density (g / cm 3 ) | calculated: [1.85] |
| Cleavage | Please complete |
| colour | dirty white to brownish yellow |
| Line color | White |
| transparency | transparent |
| shine | Silky gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.475 n β = 1.480 n γ = 1.488 |
| Birefringence | δ = 0.013 |
| Axis angle | 2V = 70 ° (measured); 78 ° (calculated) |
| Other properties | |
| Chemical behavior | water soluble |
Dietrichite is a very rarely occurring mineral from the mineral class of "sulfates and relatives" (see classification ). It crystallizes in the crystal system with the composition ZnAl 2 [SO 4 ] 4 · 22H 2 O, so from a chemical point of view it is a water-containing zinc - aluminum- sulfate.
Dietrichite is transparent and usually develops fibrous crystals in turf-shaped aggregates as well as crusts and efflorescence from dirty white to brownish-yellow color with white streak color .
Etymology and history
Dietrichite was first discovered in the " Baia Sprie Mine" (also Felsőbánya Mine ) in Romania and described in 1878 by J. Freiherr von Schröckinger, who named the mineral after Gustav Heinrich Dietrich of Příbram . He had analyzed the first samples of the mineral. Baron von Schröckinger himself referred to the mineral as zinc alum . This designation is no longer used today and is inasmuch incorrect because alums have the chemical composition M I M III (SO 4 ) 2 · 12 H 2 O.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the dietrichite belonged to the mineral class of "sulfates, selenates , tellurates , chromates , molybdates and tungstates " and there to the department of "water-containing sulfates without foreign anions ", where it belongs together with Apjohnit , Bílinit , Halotrichit , Pickeringit , Redingtonit and Wupatkiit the "Halotrichitgruppe" with the system number. VI / C.12 formed.
The 9th edition of Strunz's mineral systematics , valid since 2001 and used by the International Mineralogical Association (IMA), also assigns dietrichite 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". This section is, however, 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 “With only medium-sized cations”, where it is found together with apjohnite, caichengyunite, bilinite, halotrichite, pickeringite, redingtonite and Wupatkiit the "halotrichite group" with the system no. 7.CB.85 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns dietrichite to the class of "sulfates, chromates and molybdates" and there in the department of "water-containing acids and sulfates". Here it is together with apjohnite, bilinite, halotrichite, pickeringite, redingtonite and wupatkiite in the "halotrichite group (monoclinic with 22 H 2 O)" with the system no. 07/29/03 within the sub-section “ Water-containing acids and sulfates with A (B) 2 (XO 4 ) 4 × x (H 2 O) ”.
Crystal structure
Dietrichite crystallizes monoclinically in the space group P 2 1 / a (space group no. 14) with the lattice parameters a = 21.38 Å ; b = 24.43 Å; c = 6.24 Å and β = 100.1 ° and 4 formula units per unit cell .
properties
Dietrichit is soluble in water.
Education and Locations
Dietrichit is subsequently formed as a weathering product in disused mines.
So far (as of 2012) fewer than ten locations for dietrichite are known. In addition to its type locality Baia Sprie, the mineral occurred in Romania at Roșia Montană ( Goldbach ).
Other sites are the “Capillitas Mine” in the Andalgalá department in Argentina, Mount Isa in Australia, on a slag dump near Plovdiv in Bulgaria, in the “Boccheggiano Mine” near Montieri in Italy, near Les Valettes on Mont Chemin in the Swiss canton of Valais and near Ducktown, Tennessee and the Gold Hill Mine in Tooele County, Utah in the United States of America.
See also
Web links
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 - Dietrichite
- ↑ a b John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Dietrichite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.2 kB )
- ↑ a b c Mindat - Dietrichite
- ↑ Freiherr von Schröckinger: Dietrichit, a new alum from Hungary , in: Negotiations of the Imperial-Royal Geological Institute , 1878, pp. 189–191 ( PDF 376.4 kB )