The second part of fluorescence is the ability to emit light. Once light energy is absorbed, it has to be dissipated, which usually occurs as heat. But some compounds dissipate the energy by converting it back to light. This light is then emitted from the compound making it appear as if it has a slight glow. Many types of fluorescence material are encountered everyday: powder in fluorescent lights, dyes in highlighter ink, security features in official documents, compounds in minerals/gemstones, and phycocyanin in algae blooms.