Christite
- IMA 1976-015
Christit is a very rarely occurring thallium - mercury mineral from the mineral class of " sulfides and sulfosalts ." It crystallizes in the monoclinic crystal system with the chemical composition TlHg [ ASS3 ] and has so far been found only in the form of small, underdeveloped crystal grains to about one millimeter in size.
Christit is translucent to opaque and light orange to dark - ruby color. It is similar to realgar, but is darker. On the dash panel leaves Christit a light orange to yellow line.
Etymology and history
Was first discovered in the Christit " Carlin Gold Mine" in Elko in Lynn District, Eureka County in the U.S. state of Nevada. This has been described mineral in 1977 by Arthur S. Radtke, Frank W. Dickson, John F. Slack and Kevin L. Brown, who named the mineral after Charles Louis Christian ( 1916-1980 ), for his outstanding contributions in the fields of crystallography, to appreciate mineralogy and geochemistry.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz Christit belonged to the mineral class of " sulfides and sulfosalts " and then to the Department of " thio ", where he, along with Ellisit, Erniggliit, Hatchit, Laffittit, ROUTHIERITE, Sicherit Stalderit and Wallisit the unnamed group II/E.12 formed.
The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Christit also in the class of " sulfides and sulfosalts ," there, however, in the newly defined division of the " sulpho with SnS as a model " a. This department is also further divided according to the conditions prevailing in the interconnect metals, so that the mineral is found according to its composition in the subsection " Using Thallium (Tl) ", where it forms the unnamed group 2.HD.15 the only member.
The mainly common in English-speaking classification of minerals according to Dana assigns the Christit in the class of " sulfides and sulfosalts " and there in the department of " thio " one. Here he is with Laffittit and Daliranit in the unnamed group 03:04:10 within the subdivision " sulfosalts with the ratio 3 > z / y and the composition (A ) i ( A2 ) j [ Bycz ], A = metals, B = semimetals to find C = non-metals ".
Modifications and varieties
The compound is dimorphic, that is found in nature in addition to the monoclinic Christit more than tetragonal crystallizing ROUTHIERITE ago.
Education and Locations
Christit usually forms with realgar, orpiment and Lorandite socialized in hydrothermal barite veins and mineralized carbonaceous silty dolomite rocks and in thallium - rich Erzlinsen in stratabound deposits mercury. Other accompanying minerals include Getchellite, marcasite and pyrite.
Since Christit is one of the very rare mineral formations, he has been able (as of 2011) are detected only at a few localities. Apart from its type locality " Carlin Gold Mine" in Elko, the mineral in the United States occurred still in the " Getchell Mine" with Adam peak in Humboldt County ( Nevada), in the Lanmuchang Tl (Hg) deposit in a circle Xingren in the Chinese province Guizhou, in the " Zareh Shuran Mine" at Takab in the Iranian province of West Azerbaijan, as well as Allchar ( Alsar ) in the Macedonian district Roszdan.
Crystal structure
Christit crystallizes in the monoclinic space group P21 / n ( Raumgruppen-Nr. 14) with the lattice parameters a = 6.11 Å; b = 16.19 Å; c = 16.19 Å and β = 96.7 °, and four formula units per unit cell.
The structure consists of ASS3 pyramids, which are connected by HgS4 tetrahedra to form a two-dimensional layer parallel to {010 }. The thallium atoms are located between the layers and keep them together by weak bonds, which explains the observed perfect cleavage along { 010 }.