Kogarkoite

• IMA 1970-038

Kogarkoit is a rarely occurring mineral from the mineral class of " sulfates ". It crystallizes in the monoclinic crystal system with the chemical composition Na3 [ F | SO4 ] and usually develops granular or earthy aggregates, but also pseudo-hexagonal crystals, which can be either colorless or white to pale blue color.

Etymology and history

Was first found Kogarkoit 1973 in " Umbosero Mine " on the mountain Alluaiw in the Lovozero massif ( Ловозеро ) on the Kola Peninsula in Russia and described by Adolf Pabst and WN Sharp, who named the mineral after the Russian geochemist and Petro Login Lija Nikolaevna Kogarko.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of the Kogarkoit belongs to the department of " water clear sulfates with foreign anions ." The new Strunz'sche Mineral classification divided here, however, precisely according to the size of the cations involved, and therefore the mineral is in accordance with the subdivision "With only large cations ", where it forms the unnamed group 7.BD.15 the only member.

The commonly used in English-speaking classification of minerals according to Dana assigns the Kogarkoit also in the class of sulfates, there, however, in the department of " water clear sulfates with hydroxyl or halogen, and the general composition (AB ) m ( XO4 ) PZQ, where m is: p> 2:1 "where the unnamed group he is also the only member of 30.1.6.

Education and Locations

Kogarkoit created by Resublimation from the steam of hot springs.

Worldwide, Kogarkoit so far (as of 2010) are detected in about 10 localities, so among other things on the Mont Saint- Hilaire in the Canadian region Montérégie, the Suswa volcano in Kenya's Rift Valley province, as well as several hot springs in Chaffee County ( Colorado) and Colfax County ( New Mexico) in the USA.

Crystal structure

Kogarkoit crystallizes in the monoclinic space group P21 / m with lattice parameters a = 18.07 Å; b = 6.96 Å; c = 11.44 Å and β = 107.7 °, and 12 formula units per unit cell.