Best known for its golden-amber colored barite crystals, the Elk Creek area of Meade County, South Dakota, also produces buttery yellow calcite crystals that are fluorescent under all UV wavelengths. The primary occurrence of this material is located along the bank of Elk Creek in the Black Hills of Western South Dakota, where the calcite crystals have formed within the hollow interiors of calcareous concretions found in the surrounding Cretaceous age shale. The calcite shows a similar creamy honey-colored fluorescent response under all UV wavelengths, brightest under long wave. The size of this specimen is 13 x 9 x 8 cm, and it weighs 742 gms.
Macro image showing detail of calcite crystals photographed under short wave UV (254nm). FOV = 24mm.
Click on the above images for a larger view and UV wavelength information.