Cleiophane, an interesting variation of Sphalerite that exhibits a short-lived pop of blue phosphorescence fading to deep red after exposure to 365 nm (LW) UV.  This contrasts sharply with the bright orange the Cleiophane fluoresces. Red Willemite glows bright green under 254 nm shortwave UV which the Cleiophane fluoresces orange. The blue to red after-flash phosphorescence only occurs under Longwave UV.. Collected from the then-active, legendary Franklin Mine in Franklin NJ, one of the most unique geological assemblages on the planet. Franklin Mine, Franklin, Sussex County, New Jersey, USA. Photographed under 254 and 365 nm UV light. 3" x 2.5" x 1", 4.7 oz.