Sulfur [S] and salmiac xx [(NH4)Cl], efflorescence due to heap fire

The element sulfur and the ammonium chloride salmiac are normally formed on volcanoes. A wide variety of gases emerge from the depths of the earth through crevices and cracks, from which, for example, elemental sulfur and salmiac can separate. In this case, however, the honey-yellow and white crystals were formed during a smoldering fire at a coal mine dump in the Ruhr region.