Manganvesuvianite

• IMA 2000-040

Manganvesuvianit is a very rarely occurring mineral from the mineral class of " silicate and germanate ". It crystallizes in the tetragonal crystal system with the chemical composition CA19 (Al, Mg, Fe2 ) 13 ( SiO 4 ) 10 ( Si2O7 ) 4O (F, OH) 9 and is found in the form of thin, prismatic crystals of a few millimeters to a few centimeters in length and red reddish-brown or black color.

Etymology and history

Was named the mineral in terms of its close relationship with the vesuvianite, but with the difference of the manganese excess in the chemical composition.

The Manganvesuvianit was first discovered in 2000 in the " Wessels Mine " at Hotazel ​​in the South African Kalahari and described by T. Armbruster, E. Gnos. , R. Dixon, J. Gutzmer, C. Hejny, N. Döbelin and O. Medenbach.

Classification

In the now outdated nomenclature of minerals by Strunz ( 8th edition ) of the Manganvesuvianit still belongs to the general ward of the "Group silicates ( Sorosilikate ) ", where it forms a separate group together with Fluorvesuvianit, vesuvianite and Wiluit.

Since the revision of the Strunz'schen Mineral classification in the 9th edition also this department is precisely divided according to the type of silicate complexes occurring in the compound and the coordination of the cations involved. The Manganvesuvianit is in accordance with the unchanged on associated minerals Vesuvianitgruppe in the new subdivision of the " group silicates with mixed SiO4 and Si2O7 groups; Cations in oktahedraler and greater coordination. "

The commonly used in English-speaking classification of minerals according to Dana assigns the Manganvesuvianit also in the Department of the silicates group, however, there in the subdivision of " group silicates with insular, mixed, individual and larger groups and cations in tetrahedral and higher coordination; Single and double groups (n = 1,2) ", where he also, together with Fluorvesuvianit, vesuvianite and Wiluit own group Vesuvianitgruppe.

Education and Locations

Manganvesuvianit formed by hydrothermal processes of primary manganese ore veins and Druze.

Except at its type locality, the " Wessels Mine " in South Africa, the mineral was only in the " Harstigen Mine" at Pajsberg / Filipstad in Sweden demonstrated (as of 2009).

Crystal structure

Manganvesuvianit crystallizes in the tetragonal crystal system in the space group P4 / n with lattice parameters a = 15.575 Å and c = 11.824 Å and two formula units per unit cell.