Dypingit z produktů hořící haldy v Radvanicích u Trutnova (Česká republika)

A very rare mineral dypingite, Mg5(CO3)4(OH)2·5H2O, was determined at samples from the coal burning pile localized 1.5 km S from Radvanice near Trutnov (eastern Bohemia, Czech Republic). This is the first occurrence of this mineral in the Czech Republic. Dypingite occurs as snow-white hemispherical to spherical aggregates up to 1 mm in size formed by tiny acicular crystals on slag material in association with aragonite. Its X-ray powder diffraction data correspond very well with published ones. The results of energy dispersive analysis confirm cation composition of studied dypingite, dominant Mg is accompanied by only traces of Ca. Its formation is associated with low-temperature weathering processes taking place in an already cooled, burnt-out coal dump material.