Locality: Jáchymov, Jáchymov District, Krušné Hory Mts., Karlovy Vary Region, Czech Republic
Size: 37 mm x 15 mm x 9 mm (1.5 in. x 0.6 in. x 0.3 in.)
Weight: 3.8 g (0.14 oz.)
White brassite crystals formed as an alteration product of rosslerite. Thumbnail specimen from the type locality. Although neither rosslerite nor brassite are regarded as fluorescent in UV light, this specimen shows a slight fluorescence in short wave UV light.