Fritzscheit

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Fritzscheit
General and classification
chemical formula Mn [UO 2 | VO 4 ] 2 · 4 H 2 O
Mineral class
(and possibly department) 		Oxides and hydroxides (8th edition: phosphates, arsenates and vanadates)
System no. to Strunz
and to Dana 		4.HB.15 ( 8th edition : VII / E.01)
40.02a.25.01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group Pnam (No. 62, position 6)Template: room group / 62.6
Lattice parameters a  = 10.59  Å ; b  = 8.25 Å; c  = 15.54 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 2.5 to 3
Density (g / cm 3 ) 3.504
Cleavage completely after {001}; clearly after {100}
colour reddish brown to red
Line color brownish white
transparency translucent to translucent
shine Glass gloss, pearlescent
radioactivity very strong

Fritzscheit is a very rarely occurring mineral from the mineral class of " oxides and hydroxides " (formerly "phosphates, arsenates, vanadates"). It crystallizes in the orthorhombic crystal system with the chemical composition Mn [UO 2 | VO 4 ] 2 · 4 H 2 O. However, since the vanadate complex VO 4 can partially be replaced by a corresponding proportion of the phosphate complex PO 4 diadoch , the Formula Mn 2+ (UO 2 ) 2 (VO 4 , PO 4 ) 2 · 4 H 2 O given.

Fritzscheit usually develops translucent to transparent crystals with a leafy to tabular habit and reddish-brown to red color with a brownish-white streak color . The crystal surfaces have a glass-like to mother-of-pearl shine .

Etymology and history

The mineral was first discovered in 1865 in the Georg-Wagsfort-Fundgrube belonging to the Union United Field in Fastenberg in Wittigsthal near Johanngeorgenstadt in the Ore Mountains ( Saxony ) and described by August Breithaupt , who named it in honor of Carl Julius Fritzsche (1808–1871) German chemist and professor at the University of St. Petersburg , called Fritzscheit.

Since samples from Nejdek ( Neudek ) in the Ore Mountains in the Czech region of Karlovarský kraj ( Karlsbad ) were also used to analyze the chemical composition , this site is also considered a type locality .

Type material of the mineral is in the Natural History Museum Vienna in Austria under the catalog no. Aa 5699 kept.

classification

In the old classification of minerals by Strunz (8th edition) Fritz log still belonged to the mineral class of "phosphates, arsenates, vanadates" and then to the Department of "uranyl phosphates and Uranylvanadate" where he along with Autunit , Heinrichit , Kahlerit , Metanatroautunit , Novácekite , Sabugalit , Saléeit , Torbernit , Trögerit , Uranocircit , Uranospinit and Zeunerit formed a separate group.

Since the revision of Strunz's mineral systematics in the 9th edition , however, many departments have been redefined and subdivided more precisely according to composition and structure, so that the mineral is now in the mineral class of "oxides and hydroxides" and the department " V [5,6] (coordinated) vanadate ”, where it is assigned to the subdivision“ Uranyl group vanadates (sorovanadates) ”due to its crystal structure. Here the Fritzscheit forms a separate group together with Curienit and Francevillit .

The systematics of minerals according to Dana , which is common in the English-speaking world , still assigns the Fritzscheit to the class of "phosphates, arsenates and vanadates". There he is the only one of his group in the unnamed subdivision 40.02a.25 of the department of “Hydrated Phosphates etc., with A 2+ (B 2+ ) 2 (XO 4 ) • (H 2 O), with (UO 2 ) 2+ ".

Crystal structure

Fritzscheit crystallizes orthorhombically in the space group Pnam (space group no. 62) with the lattice parameters a  = 10.59  Å ; b  = 8.25 Å and c  = 15.54 Å and 4 formula units per unit cell .

properties

The mineral is by its uranium content strongly up to 47.65% radioactively and has a specific activity of about 85 k Bq / g (compared to natural potassium 0.0312 kBq / g).

Education and Locations

The exact formation conditions are not known, but the Fritz log was found in hematite - deposits .

As a very rare mineral formation, Fritzscheit was only detected in a few samples from less than 10 sites. In addition to its type localities Georg-Wagsfort-Fundgrube in Germany and Nejdek in the Czech Republic, the mineral has so far (as of 2017) only been found in the mining area Schneeberg in the Ore Mountains (Germany), Přebuz ( early penance in Karlsbad, Czech Republic) and near Autun in the French region of Burgundy become.

Precautions

Due to the toxicity and radioactivity of the mineral, mineral samples from Fritzscheit should only be kept in dust- and radiation-proof containers, but above all never in living rooms, bedrooms or workrooms. Absorption into the body (incorporation, ingestion ) should also be prevented in any case and, for safety, direct body contact should be avoided and respiratory protection mask and gloves should be worn when handling the mineral .

See also

Web links

Individual evidence

  1. ↑ 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.  256 .
  2. ↑ a b Webmineral - Fritzscheite (English)
  3. ↑ a b c Fritzscheite . 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; 61  kB ; accessed on June 19, 2017]).
  4. ↑ IMA / CNMNC List of Mineral Names - Fritzscheite (English, PDF 1.8 MB)
  5. ↑ Thomas Witzke : Discovery of Fritzscheit at www.strahl.org
  6. ↑ a b List of localities for Fritzscheit in the Mineralienatlas and Mindat