Zunyite

Zunyit is a rarely occurring mineral from the mineral class of " silicates and Germanates ". It crystallizes in the cubic crystal system with the chemical composition Al12 [( OH) 14 | Cl | AlO4 | Si5O16 ] and are found most often in the form of well-developed, tetrahedral or pseudo - octahedral crystals ( possibly cubic combinations ).

Reiner Zunyit is colorless and transparent, and the crystal faces have a glass-like luster. He can, however, appear white or accept a flesh -red color by multiple refraction due to twinning, lattice defects or foreign impurities or inclusions, the transparency decreases accordingly.

With a Mohs hardness of 7 Zunyit one of the hard minerals, which mineral quartz as the reference are similar in position to carve the window glass.

Special Features

Under UV light, show some Zunyite red fluorescence, similar to that of neon-colored highlighters.

Etymology and history

Was first discovered in the Zunyit the " Zuni Mine" ( Zuni Mine) at the Anvil Mountain near Silverton in Colorado and described in 1883 by William Francis Hillebrand ( 1853-1925 ), who named the mineral after its type locality.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Zunyit belonged to the mineral class of " silicates and Germanates " and then to the Department of " group silicates ( Sorosilikate ) " where he was the only member of the independent group VIII / C. 36 was formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Zunyit also included in the category of " silicates and Germanates " and there in the department of " group silicates ( Sorosilikate ) ". This division, however, is further subdivided according to the nature of the silicate group formation, the possible presence of other anions and the coordination of the cations involved, so that the mineral according to its composition and its construction in the subsection " group silicates with Si3O10, Si4O11, etc. anions; Cations can be found in octahedral and / or greater coordination " where it also forms the unnamed group 9.BJ.55 the only member.

The mainly common in English-speaking classification of minerals according to Dana assigns the Zunyit in the class of " silicates and Germanates " there, however, in the already fine divided department of " group silicates: Insular ( Si3O10 ) and larger non-cyclic groups with Si3O10 groups " one. Here he is the only member of the unnamed group 57.03.01 within the sub-division of " group silicates: Insular ( Si3O10 ) and larger non-cyclic groups with Si5O16 groups " to find.

Education and Locations

Zunyit forms in high-grade, aluminous schists and hydrothermally -formed volcanic rocks. Accompanying minerals include alunite, diaspore, hematite, kaolinite, pyrite, pyrophyllite, quartz and rutile.

Overall, Zunyit so far (as of 2011) are detected in 75 localities. Apart from its type locality " Zuni Mine" was found the mineral in the USA or in several places in the Dome Rock Mountains, near San Manuel ( Pinal County) and Alum Gulch (Santa Cruz County) in Arizona; at Mount Robinson ( Custer County), at Horse Creek ( Dolores County), in the Red Mountains ( Ouray County), in Saguache County and at other locations in San Juan County, Colorado; at Butte, Montana; Buckskin ( Douglas County), Scraper Springs ( Elko County) and Robinson ( White Pine County) in Nevada; at Clubb Mountain and at Hillsborough in North Carolina and in the Tintic Mountains in Utah.

Other localities lie in Bejaia in Algeria; King George Iceland in Antarctica; Catamarca, La Rioja and Salta in Argentina; Tasmania in Australia; in Azerbaijan; at Cerro Tazna in the Bolivian Cordillera de chichas; Brumado in the Brazilian state of Bahia; at Panagjurischte and Chelopech ( Sofia Province ) in Bulgaria; at several locations in the Atacama region in Chile; in Zijinshan and Qinglong ( Qinhuangdao ) in China; on Honshu in Japan; on Vancouver Iceland in Canada; at Ojuu Tolgoi in Mongolia; in the Moroccan province of Ouarzazate ( Souss- Massa- Draâ ); at Otuzco in the Peruvian province of La Libertad; Mankayan in the Philippines; in Apuseni Mountains in Romania; at Bor in Serbia; in the regions of Slovakia Banská Bystrica and Košice; in the Spanish province of Almería; at Doornfontein North Cape in South Africa; in the Hungarian Fejér county and in Embleton ( Cumbria ) in the United Kingdom.

Crystal structure

Zunyit crystallized cubic in space group F43m ( Raumgruppen-Nr. 216 ) with the lattice parameters a = 13.88 Å and four formula units per unit cell.