Briartite

• IMA 1965-018

Briartit is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts ." It crystallizes in the tetragonal crystal system with the chemical composition of Cu 2 (Fe, Zn) and thus, the zinc GES4 analogue of Barquillit ( Cu2 ( Cd, Fe) GES4 ). The values ​​given in the parentheses of the elements iron and zinc may be in the formula each represent each other (substitution, Diadochie ), but are always in the same proportions to the other components of the mineral.

Briartit is opaque in any form and by gray, and gray-blue in reflected light, color. So far, he could be found in other sulfides only in the form of small grains to about two millimeters in diameter and as inclusion.

Etymology and history

Was first discovered in the Briartit " Kipushi Mine" (also called " Prince Léopold Mine" ) in Kipushi in the Democratic Republic of Congo. He was described in 1965 by J. Francotte, R. Moreau, R. Otten Petersburg and C. Lévy, the named the mineral after Gaston Briart who studied the Kipushi deposit.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Briartit belonged to the mineral class of " sulfides and sulfosalts " and then to the Department of " sulfides with the molar ratio of metal: sulfur, selenium, tellurium ≈ 1: 1" where he along with Barquillit, Černýit, Famatinit, Ferrokësterit, Hocartit, Kesterite, Kuramit, Luzonit, Permingeatit, Petrukit, Pirquitasit, Rhodostannit, Sakuraiit, stannite, Toyohait and Velikit the " stannite - group " with the system no. II/C.06 formed.

The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Briartit also in the class of " sulfides and sulfosalts ," there, however, in the department of " Sulfoarsenate " one. This department is also further divided according to the crystal structure, so that the mineral is " with (As, Sb) Sulfarsenate S4 tetrahedra " to find according to its construction in the subdivision of where it together with Barquillit, Famatinit, Luzonit and Permingeatit the " Luzonit group "with the system no. 2.KA.10 forms.

The mainly common in English-speaking classification of minerals according to Dana assigns the Briartit into the class of " sulfides and sulfosalts " and there in the department of " sulfide minerals ." Here he is with Hocartit, Barquillit, Černýit, Ferrokësterit, Kesterite, Kuramit, Pirquitasit, Sakuraiit, stannite and Velikit in the " Stannitgruppe ( Tetragonal: I42m ) A2BCS type " with the system no. 02:09:02 within the subdivision " sulfides - including selenides and tellurides - with the composition AmBnXp, with (m n): p = 1:1" to find.

Education and Locations

Briartit forms as a rare inclusion in other germanium - gallium - bearing sulfides. As an accessory mineral occur among others chalcopyrite, galena, germanite, Renierite, sphalerite and tennantite.

Apart from its type locality " Kipushi Mine" (also called " Prince Léopold Mine" ) in the Democratic Republic of Congo, the mineral found so far (as of 2012) still in the deposit " Plan d' Argut " at Argut lingerie in the department of Haute -Garonne and at Bancaïroun ( Guillaume ) in the Alpes -Maritimes in France, the " Kamariza Mines " at Agios Konstantinos in the Greek region of Attica, in the " Tsumeb Mine " in Namibia, in the " Kabwe Mine" (also called " Broken Hill Mine" ) at Kabwe in Zambia, the " Teresita Mine" at Riosa and Barquilla Sn -Ge -Cd -Cu -Fe deposit in Salamanca in Spain and in the " INEXCO Mine" at Jamestown in the U.S. state of Colorado.

Crystal structure

Briartit crystallized tetragonal in the space group I42m ( Raumgruppen-Nr. 121) with the lattice parameters a = 5.32 Å and c = 10.51 Å and two formula units per unit cell.