Lorenzenite

• Ramsayit

Loren Zenit is a rarely occurring mineral from the mineral class of " silicates and Germanates ". It crystallizes in the orthorhombic crystal system with the idealized chemical composition Na2Ti2 [ O3 | Si2O6 ], that is chemically a sodium titanium silicate, which structurally belongs to the chain silicates and band silicates. As a second admixture may also contain a small proportion of niobium, iron, fluoride, and zirconium.

In pure form, Loren Zenit is colorless and transparent. But it may also appear white and light brown violet, light pink to accept malvenähnliche or brown to black color, the transparency may decrease according to total opacity by foreign admixtures by multiple refraction due to lattice defects or polycrystalline training.

Loren Zenit usually developed prismatic crystals with acicular habit dicktafeligem up, but also comes in the form of fibrous and felted or lamellar mineral aggregates before.

Special Features

Under short-wave UV light indicate some Loren Zenite a light yellow to dull green fluorescence, similar to that of neon highlighters.

Etymology and history

Was first discovered Loren zenith near the former settlement Narsaarsuk (also Narssârssuk ) and described in northwestern Greenland in 1897 by G. Flink, who named the mineral after the Danish mineralogist Johannes Theodor Lorenzen ( 1855-1884 ). The chemical analysis took R. Mauzelius ago.

1922 was an expedition under AE Fersman in nepheline syenite on the Russian Kola Peninsula a related mineral, first described by E. Kostyleva ( published in 1923 ) and was named after the Finnish geologist William Ramsay Ramsayit. However Kostyleva noticed during its first description the great similarity with Loren zenith in terms of chemical composition and crystal form and suspected that the two minerals could be identical. Using further analysis by Barth and Berman 1930, and by Kraus and Mussgnuga 1941 was used to correct the structural data of Loren zenith, thus proving that Ramsayit and Loren Zenit were virtually identical. Only the composition differed slightly in that the analyzed from Mauzelius Loren Zenit- sample a significant proportion of zirconium ( 11.92% in the form of ZrO2) contained. The re-analysis of a very pure sample of Loren Zenit- type material by TG Sahama however revealed that the zirconium content was negligible as well as the Ramsayit. Even the also detected in both samples foreign admixture of niobium was higher. However, since on the one hand, the analyzed from Mauzelius original material was no longer available and on the other the description of Flink lacked detail the method of analysis, Sahama could not resolve with certainty whether Mauzelius ' analysis was flawed or the zirconium content simply a contamination of the sample represented. With regard to the amount of the share of nearly 12 %, however, it is doubtful whether Mauzelius ' sample could have been so unclean. Although the capability exists because of the found at the type locality Narsaarsuk socialization with the sodium zirconium silicate Elpidite, however, this mineral can be very easily separated from the Loren zenith.

In German- speaking countries or western international, supported by the International Mineralogical Association (IMA ), sat down in the meantime the name Loren Zenit (English Loren Zenite ) by, while the term Ramsayit is still widespread in the Russian -speaking world. The Finnish mineralogist Wilhelm Ramsay, were granted in 2004 by the newly discovered mineral Wilhelmramsayit still an internationally recognized award.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz of Loren Zenit belonged to the department of " chain silicates and phyllosilicates ( inosilicates ) " where he, along with Balipholit, Ferrokarpholith, Kalikarpholith, Karpholith, Kukisvumit, Lintisit, Magnesiokarpholith, Manganokukisvumit Paravinogradovit, Vanadiokarpholith and vinogradovite the " Karpholithgruppe " with the system no. VIII/F.03 formed.

The valid since 2001 and used by the IMA 9th edition of the Strunz'schen Mineral classification assigns the zenith Loren also in the department of " chains and chain silicates ( inosilicates ) ". However, this is further divided according to the structure of the chain formation, so that the mineral according to its construction in the subdivision " chain and chain silicates with 2- periodic single chains Si2O6; with additional O, OH, H2O to find related pyroxene minerals ", where it forms the unnamed group 9.DB.10 the only member.

The mainly common in English-speaking classification of minerals according to Dana assigns Loren zenith in the department's " chain silicate minerals " one. Here he is as the namesake of " Loren Zenit group " with the system no. ": With chains P = 2 Simple unbranched chains, W = 1 chain silicates " to find 65.01.06 and the other members Kukisvumit, Lintisit, Manganokukisvumit and Punkaruaivit within the subdivision.

Education and Locations

Loren Zenit forms magmatic in alkaline syenites and syenitic pegmatites. Accompanying minerals occur among others aegirine, apatite, Arfvedsonite, Astrophyllite, Elpidite, eudialyte, ilmenite, Låvenit, loparite, microcline, nepheline, manganese Neptunite, Rinkit and titanite.

A rare mineral formation Loren Zenit has so far (as of 2013) only from a few localities or in small number of known ( according to mindat.org around 70 localities ). Apart from its type locality Narsaarsuk the mineral in Greenland so far could be found at Narsaq only on " Gardinerkomplex " near Kangerlussuaq and Ilímaussaq complex.

Known localities in Germany are the quarry " Michel Berg" on Katzenbuckel in Baden -Württemberg and the quarry " Caspar " on Ettringer Bellerberg at Ettringen in North Rhine-Westphalia Eifel.

In Russia, especially the Kola peninsula was known as a rich area due to the complex history of the Minerals Fund, with most Loren Zenit finds from the mountain ranges of Chibinen and the Lovozero Tundra come. Worth mentioning in detail, among other things of the mountain flora in the Lovozero tundra massif, where crystals were up to eight centimeters found.

Other localities lie including Canada, Libya, Morocco, Norway, Spain, South Africa, as well as Arkansas and New Mexico in the United States of America.

Crystal structure

Loren Zenit crystallizes in the orthorhombic space group PNCA ( Raumgruppen-Nr. 60) with the lattice parameters a = 14.49 Å; b = 8.71 Å and c = 5.23 Å and four formula units per unit cell.