Barite, Cave-In-Rock, Illinois
Cluster of white, bladed, barite crystals without matrix, with needle-like, off-white calcite crystals occurring between the central barite blades on one side of the specimen. It was collected from one of the many fluorspar (fluorite) mines in the Cave-In-Rock area of southern Illinois. This barite shows exceptionally bright white to white/blue fluorescence with bright phosphorescence under all UV wavelengths. The size of this specimen is 67 x 57 x 37 mm, and it weighs 95 grams.
Photograph taken under short wave UV (254nm). The barite fluoresces blue/white and the calcite cream/tan. See the following image gallery for photographs taken under other wavelengths:
Click on the above images for a larger view and UV wavelength information.