This is a cluster of milky white calcite crystals from the Sweetwater Mine, Ellington, Viburnum Trend District, Reynolds Co., Missouri, that shows a spectacular multi-colored fluorescent response under all UV wavelengths. Under short wave UV (254nm) the calcite fluoresces red, but shows a bright saturated orange response under mid wave UV (302nm), and a pink/magenta response under long wave UV (365nm). 54.1 x 40.8 x 35.8 mm, 52 grams.
In the photo montage above, the specimen is shown under visible light (upper left), short wave UV (upper right), long wave UV (lower left), and mid wave UV (lower right).