Cylindrite

• Cylindrit

Researcher is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the triclinic crystal system with the composition FeSn4Pb3Sb2S14, is so chemically seen an iron -tin-lead -antimony sulpho salt.

Researcher is opaque in any form and develops unusual crystal forms, which consist of individual, one above the other rolled bowls with cylindrical or conical, rarely spherical habit and are often arranged in tufted or fan-shaped aggregates of up to five centimeters in diameter. Its color varies from gray and black lead, his stroke color, however, is purely black. Fresh samples exhibit a metallic luster.

Special Features

From cold acids cylindrite is hardly attacked. Hot hydrochloric and nitric acids dissolve it, however gradually. Before the blowpipe on charcoal cylindrite melts easily to the ball and gives sulphurous acid and a fitting of lead oxide and tin oxide from.

Etymology and history

Was first discovered Researcher in the " Mina Santa Cruz " (Santa Cruz Mine ) near Poopó in the Bolivian department of Oruro and described in 1893 by Friedrich August Frenzel, who roll the mineral because of its characteristic cylindrical to cylindrical shape from the ancient Greek word κυλίνδειν [ kylíndein ] for or roll named.

Classification

Already in the now outdated but still in use 8th edition of the mineral classification by Strunz was one of cylindrite for mineral class of " sulfides and sulfosalts " and then to the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 was named the " Researcher group " with the system no. Formed II/C.17 and the other members Abramovit, Coirait, Franckeit, Herzenbergit, Incait, Lévyclaudit, Mohit, Potosíit, Stistait, Suredait and Teallit.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the cylindrite also in the class of " sulfides and sulfosalts ," there, however, in the department of " sulfosalts with SnS as an example " a. This department is also further divided according to the conditions prevailing in the interconnect metals and the structure so that the mineral is found according to its composition in the subsection "With SnS and PbS archetype structural units " where there is only together with Abramovit and Lévyclaudit the named also after him " Researcher group " with the system no. 2.HF.25a forms.

The mainly common in English-speaking classification of minerals according to Dana assigns the Researcher in the class of " sulfides and sulfosalts " and there in the department of " thio " one. He is also named as the " Kylindritgruppe " with the system no. 03.01.04 along with Franckeit, Incait, Potosíit, Abramovit and Coirait within the sub-division of " sulfosalts with the ratio z / y > 4 and the composition (A ) i ( A2 ) j [ Bycz ], A ​​= metals, B = semimetals to find C = non-metals ".

Education and Locations

Researcher is formed hydrothermally in tin transitions. Accompanying minerals include Boulangerite, Franckeit, galena, Incait, Jamesonite, cassiterite, Potosíit, pyrite, sphalerite, stannite and Teallit.

A rare mineral formation cylindrite has so far (as of 2011) are detected only at a few localities. So far are considered to be known around 20 points Fund. Apart from its type locality " Santa Cruz Mine" the mineral still occurred in Bolivia in the nearby also at Poopó " San Francisco Mine" as well as within the province Poopó still in the " Trinacria mine " on. These mines are also known for their rich mineral discoveries with crystal sizes up to about 5 cm in length. In addition, cylindrite still found in several other mines in the Oruro Department and the Potosí Department.

Other localities, among other things, the Oploca Vein system of " Oploca Mine" in the Pirquitas deposit the Argentine province of Jujuy, the Sukhoi Log deposit in Bodaibo in the Russian Oblast Irkutsk ( Siberia ) and the Nikitovka deposit in the Donets Basin near Donetsk in Ukraine.

Crystal structure

Cylindrite crystallizes in the triclinic space group P1 ( Raumgruppen-Nr. 1) with a very complex crystal structure, consisting of two triclinic sublattices with the common plane (100 ), the axis a0 and the lattice parameters:

• TC: a = 11.76 Å; b = 5.79 Å; c = 5.81 Å; α = 91 °; β = 91.2 ° and γ = 95 °

• HC: a = 11.73 Å; b = 3.67 Å; c = 6.32 Å; α = 91 °; β = 91 ° and γ = 91 °

Structurally, Researcher of corrugated layers in which the pseudotetragonal ( tC ) crystallizing compound MeS alternate (Me = Pb, Sn, Ag, Fe) with deformed PbS structure and the pseudohexagonal ( hC ) crystallizing compound SnS2 with Sn in octahedral coordination.