This is a simple, but interesting fluorescent specimen that dates back to the age of the trilobites. A vein of light-colored calcite fills a fracture in a matrix of grey Wheeler shale. Under short wave UV, the calcite fluoresces bright red/orange, contrasting against the non-fluorescent shale. The calcite vein is approximately 1.5 mm wide. This specimen was collected from the world famous trilobite beds in the House Range, near Delta, Millard Co., Utah. The Wheeler shale was deposited during the Cambrian period approximately 500 million years ago, and is known for producing a great variety of finely-preserved fossils of marine invertebrates including over 500 species of trilobites. The size of this specimen is 10.0 x 6.2 x 0.7 cm.
