Kornerupine
Kornerupine is a rarely occurring mineral from the mineral class of " silicates and Germanates ". It crystallizes in the orthorhombic crystal system with the chemical composition ( □, Mg, Fe2 ) Al4 ( Mg3Al2 ) [ O4 | (OH, O) | Si2O7 | (Si (Al, B) Si) Σ3O10 ] and usually develops transparent to translucent crystals with prismatic habit, but also radial- or -grained mineral aggregates.
Reiner Kornerupine is colorless and transparent. However, it can appear white through much crystalline ( granular ) training or lattice defects, or gray, greenish, bluish, greenish brown to yellowish brown or black color accept by foreign admixtures. However, the stroke color is always white.
With a Mohs hardness 6-7 Kornerupine among the medium- hard to hard minerals and is similar to the reference mineral for hardness 6 Orthoclase with steel file still can be scratched or as the reference mineral for hardness 7 Quartz able to scratch window glass.
Etymology and history
Kornerupine was first discovered in Qeqertarsuatsiaat (Danish Fiskenaesset ) on Greenland and described in 1884 by Johannes Theodor Lorenzen ( 1855-1884 ), who named the mineral after the Danish geologist Andreas Nikolaus Kornerup ( 1857-1883 ).
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the Kornerupine belonged to the mineral class of " silicates and Germanates " and then to the Department of " island silicates with tetrahedral foreign anions ( Neso - Subsilikate ) " where he along with Boralsilit, Dumortierite, Grandidierit, Harkerit, Holtit, Magnesiodumortierit, Ominelit, Prismatin and Werdingit formed a distinct group.
The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Kornerupine 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 and the size of the cations involved, so that the mineral according to its composition in the subdivision of " group silicates with Si3O10, Si4O11, etc. anions; Cations can be found in octahedral and / or greater coordination ", where it forms the unnamed group 9.BJ.50 together with Prismatin.
The mainly common in English-speaking classification of minerals according to Dana assigns the Kornerupine in the class of " silicates and Germanates " there, however, in the already fine divided department of " group silicates: Insular, Mixed, individual and larger tetrahedral groups " field. Here he is as the namesake of the " Kornerupingruppe " with the system no. 58.01.01 and the other Member Prismatin within the sub-division of " group silicates: Insular, Mixed, individual and larger groups with cations in tetrahedral and higher coordination; Single and double groups (n = 1,2) to find ".
Education and Locations
Kornerupine usually forms in boron-rich volcanic and sedimentary rocks that have been claimed strongly metamorphosed and form amphibolite or granulite facies. Accompanying minerals include andalusite, biotite, cordierite, Dumortierite, Grandidierit, hematite, ilmenite, corundum, kyanite, magnetite, phlogopite, rutile, sapphirine, sillimanite, spinel and various tourmalines.
Overall Kornerupine has so far (as of 2011 ) were detected in 44 localities. Apart from its type locality Qeqertarsuatsiaat ( Fiskenaesset ), where with a diameter of up to 23 cm, the largest ever known crystals were found, the mineral occurred in Greenland still Bjørnesund at Sarfaq in the district Kitaa on.
Other localities lie in the Lützow -Holm and Enderbyland Bay in East Antarctica; at the Mount Riddock station and the Strangways Ranges in the Northern Territory in Australia; at Ohngaing, near the town of Mogok in Mandalay Division of Myanmar (formerly Burma); in Lac -Sainte -Marie in the Canadian Outaouais; in Jixi in China; on the Rio Mayo in Municipal de Mercaderes in the Colombian community Cauca; at Varpaisjärvi and Kittila in Finland; on Lasamba Hill and Mangari in the Kenyan Coast Province; at Ambovombe, Betroka and Mahafaly in the province of Toliara in Madagascar; in Arendal, Froland and Risr in the province of Aust-Agder and Bamble in the province of Telemark in Norway; on Chilapila Hill in Copperbelt in Zambia; at Dobšiná in Slovakia; at Port Shepstone, on Soutpansberg and in Namaqualand in South Africa; at Weligama in Matara district of Sri Lanka; in the Pamir Mountains in Tajikistan; on Mautia Hill in the Dodoma region in Tanzania; in the Labwor Hills in the district of Kotido in Uganda; at the Mase Mountain in the Morris County and on Greenwood Lake in New Jersey, at Lyonsdale in Lewis County and at Warrensburg in the same County in New York and at the Moses Rock in the San Juan County, Utah.
Crystal structure
Kornerupine crystallizes in the orthorhombic space group Cmcm ( Raumgruppen-Nr. 63) with the lattice parameters a = Å; b = Å; c = Å; α = °; β = ° and γ = ° as well as formula units per unit cell.