Tyuyamunite

Tyuyamunite is a rarely occurring uranium -vanadium mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the orthorhombic crystal system with the chemical composition Ca [ UO2 | VO4 ] 2.6 - 8H2O and usually develops massive mineral aggregates, but also rare, tabular, partly fan-shaped crystals of yellow to green-yellow color.

Special Features

The mineral is classified radioactive due to its uranium content of up to 51.8 % as very strong and has a specific activity of about 92.816 kBq / g (compared to natural potassium 0.0312 kBq / g).

The water content of Tyuyamunite is zeolitic nature, that is, depending on the ambient humidity of the crystal water content may vary. In a dry environment dehydrated Tyuyamunite to Metatyuyamunit with the formula Ca [ (UO2 ) 2 ( VO4 ) 2] · 5H2O 3.

Tyuyamunite is visually difficult by other uranyl vanadates carnotite how to distinguish, for example.

Etymology and history

Tyuyamunite was first described in 1912 by Konstantin Nenadkewitsch and after the type locality, named the Tyuya - Muyun mine in Kyrgyzstan.

The type of mineral is located at the Russian Academy of Sciences in the Mineralogical Museum " Alexander Fersman " in Moscow, Russia.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Tyuyamunite belonged to the mineral class of " phosphates, arsenates and vanadates " and then to the Department of " Uranylphosphate / arsenates and Uranylvanadate " where he along with carnotite, Curienit, Francevillite, Margaritasit, Metatyuyamunit, Metavanuralit, Sengierit, Strelkinit and Vanuralit the group of " uranyl Gruppenvanadate with [ UO2 ] 2 - [ V2O8 ] 6 - " with the system no. VII/E.11 formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of Strunz 's Mineral classification assigns the Tyuyamunite other hand, in the class of " oxides and hydroxides " and there in the department of " V [ 5,6] vanadates, " a. This is also further divided according to the crystal structure, so that the mineral is found in accordance with its construction in the subsection " uranyl Gruppenvanadate ( Sorovanadate ) " where it only with his dehydrated meta- form, the Metatyuyamunit the unnamed group 4 HB.25 forms.

The mostly commonly used in English-speaking classification of minerals according to Dana assigns the Tyuyamunite as the outdated Strunz'sche systematics in the class of " phosphates, arsenates and vanadates " one -up, but in the department of " water -containing phosphates, etc. ". Here he is with the Metatyuyamunit in the unnamed group 40.02a.26 within the sub-division of " water -containing phosphates, etc., with A2 ( B2 ) 2 ( XO4 ) × x (H2O), with (UO2 ) 2 " to find.

Education and Locations

Tyuyamunite formed in the oxidation zone of uranium - vanadium deposits on sandstone matrix. It occurs in paragenesis along with others, carnotite, Corvusit, Metatyuyamunit and Volborthit.

Worldwide has been able to be detected at several localities Tyuyamunite. The most important sites are primarily those of the Colorado Plateau in Utah and Arizona in the United States.

Crystal structure

Tyuyamunite crystallizes in the orthorhombic space group Pnan ( Raumgruppen-Nr. 52) with the lattice parameters a = 10.63 Å; b = 8.36 Å and c = 16.96 Å and four formula units per unit cell.

Security measures

When dealing with Tyuyamunite is to ensure adequate radiation protection. To prevent incorporation ( uptake into the body ), is thorough hand washing after handling with bare hands is recommended.