Natrozippeite, also known as sodium zippeite, is a secondary hydrous sodium uranium sulfate that commonly forms as efflorescent encrustations on sandstone in underground uranium mines in the western US. As is the case with many secondary uranium minerals, natrozippeite is brightly fluorescent under UV. This specimen features small yellow crystals of natrozippeite on a sandstone matrix, collected from the Little Eva mine, located north of Arches National Park, in Grand County, Utah. The natrozippeite shows a bright yellow/green fluorescent response under all UV wavelengths. Because this mineral contains uranium, it is radioactive, and emits approximately 2000 cpm. The size of this specimen is 22 x 15 x 11 mm.