The mineral crystals also interact with light causing refraction while emitting photons (quantum units of light particles) that act on human tissue. The refracted light has its wave frequency changed resulting in several colors that produce bio-photonic effects (light interference in the body cellulae of living beings which restore the energy balance). Mandel (1998) cites that bio-photonics is a language used by cells regulating all body functions. (ARRIETA, 2006; CAPRA, 2003; MANDEL, 1998; PAGNAMENTA, 1998)