The amazingly fluorescent minerals of the old Franklin Mine in New Jersey are legendary around the world. The white Calcite glows red, the Red WIllemite green This unique vintage plate preparation makes a perfect display piece, highlighting the distinct reactivities (or not, sorry Zincite and Franklinite, no glow for you) in shortwave (254 nm) UV light. 3.5" x 2.5" x .18", 2.7 oz.