Fig. 5
From: Trachyte weathering in the urban built environment related to air quality
SEM–EDS X-ray maps of a gypsum crust of Euganean trachyte prepared as epoxy-embedded cross section, with the exposed surface displayed on the top (field size: 524.5 × 407.3 µm). Details of the gypsum crystals and the fractured host rock beneath the crust are showed in the SEM-BSE photomicrographs