CRYSTAL STRUCTURE OF LAITAKARITE AS A FUNCTION OF ITS CHEMICAL COMPOSITION

Abstract

The study was done on laitakarite-bearing ore samples from the Nevskoye tin deposit in northeastern USSR and from the Orijarvi mine. In the polished sections studied, laitakarite is present as flaky grains a large as 0.8 × 0.2 mm and usually with a distinct cleavage parallel to the elongation. When examined in reflected light, the mineral was seen to be white, clearly bireflectant and strongly anisotropic with a color effect from light brown to gray. Given the observed relationship between the composition of laitakarite and its association with other minerals, we suggest that the laitakarite varieties were formed in different sulfur regimes. Consequently, the presence of one laitakarite variety or another could serve as an indicator of sulfur fugacity.