Tenebrescence is the phenomenon that occurs when a mineral changes color after exposure to UV light. The color change is temporary, and can be reversed when the material is exposed to incandescent light. Tenebrescence in natural scapolite has been documented (Fall 2005 GNI, pp. 269–271). In the case of these 16 scapolite samples, tenebrescence was observed as a moderately saturated blue color in a previously near-colorless stone. Based on the submitted materials tested, it appeared that artificially irradiating scapolite created a much stronger tenebrescent effect when the material was subsequently exposed to UV light. The material displayed tenebrescence when subjected to LWUV, but the intensity was generally greater after exposure to SWUV (figure 1, center and right). After exposure to SWUV, the visible absorption spectrum of the blue color-causing defect was measured. The resulting visible spectrum confirmed that the blue color was induced in the scapolite