Though not a stunning fluorescent material, Colemanite is typically quite bright and sometimes phosphorescent. This specimen, from the Bigadic Mine, Balikesir Province, Turkey, is quite beautiful in natural light. It's a bright bluish white in shortwave and an almost creamy yellow in longwave. This specimen is about 6 inches by 4 inches, with an inch deep cavity in the middle. Shown in SW, MW, LW, and natural. It is somewhat phosphorescent, but not worthy of a photo.