Szmikit z Chvaletic u Přelouče (Česká republika)

Abstract

A very rare mineral szmikite, Mn(SO4)·H2O, was determined at historical samples from the western part of upper level of the Chvaletice quarry (10 km W from Přelouč, eastern Bohemia, Czech Republic). This is the first occurrence of this mineral in the Czech Republic. Szmikite occurs there as soft distinctly porous crusts up to 10 cm in size formed by tiny (1 - 5 μm) transparent, imperfectly developed crystals. It is white, sometimes with a weak pink or yellow tints. Szmikite is monoclinic, space group C2/c, the unit-cell parameters refined from X-ray powder diffraction data are: a 7.063(3), b 7.6418(18), c 7.836(3) Å, β 118.14(2)o and V 372.9(4) Å3. The result of ICP OES analysis corresponds to following cation composition of studied szmikite: 0.649 apfu Mn, 0.339 apfu Mg, 0.009 apfu Fe and 0.004 apfu Ca. Vibrational (Raman and infrared) spectroscopy documents the presence of molecular water and sulphate units in the crystal structure of szmikite.