Bixbyit-(Mn) z Horní Blatné v Krušných horách - první nález v České republice

Rare Mn3+ oxide, mineral bixbyite-(Mn), was found in samples from the mine dump material of the Segen Gottes Gallery, 1.6 km NW of Horní Blatná, Krušné hory Mountains, Czech Republic. Bixbyite-(Mn) occurs as steel-gray, fine-grained aggregates up to 1 cm in size with metallic lustre in quartz gangue in association of pyrolusite. Bixbyite-(Mn) is isometric, space group Ia3, the unit-cell parameter refined from X-ray powder diffraction data is a 9.4058(3) Å with V 832.12(9) Å3. The chemical composition of the studied mineral is close to the Mn end-member of the bixbyite series with Fe contents only in the range of 0 - 0.07 apfu, in addition, minor Al contents (up to 0.03 apfu) were also determined. The contents of other - elements found - Ca, Cu, Zn and Si do not exceed 0.01 apfu, in the case of P in some analyzed points 0.02 apfu. Raman spectrum of studied bixbyite-(Mn) is also given. This is the first confirmed occurrence of bixbyite-(Mn) in the Czech Republic.