Furthermore, synthetic opals do not fluoresce under ultraviolet light. Under ultraviolet light, ammolite may fluoresce a mustard yellow. Crystals containing heavy atoms can diffract well, but also fluoresce themselves, causing interference. Spiders fluoresce under UV light and possess a huge diversity of fluorophores. Most sodalite will fluoresce orange under ultraviolet light, and hackmanite exhibits tenebrescence. The lichen does not fluoresce in ultraviolet light. This process in which fluorophores temporarily do not fluoresce is called blinking. If electrons impinge on the phosphor-coated anode plates, they fluoresce, emitting light. The quinine in tonic water will fluoresce under ultraviolet light. Photographs made of various dyes that fluoresce under ultraviolet illumination are also useful. Upon passing through a laser beam, the atoms will fluoresce (emit photons). Infected hairs usually fluoresce greenish-yellow under a Wood lamp (blacklight). These dots fluoresce blue under ultraviolet light and were used as a security feature. A 2008 study reported that ripe bananas fluoresce when exposed to ultraviolet light. In order to fluoresce, IFPs require an exogenous chromophore, biliverdin.