Stone Mania

Iridescence is an optical phenomenon of surfaces in which hue changes in correspondence with the angle from it is being viewed.  It is caused by multiple reflections in multi-layered, semi-transparent surfaces.  Some gemstones are particularly renowned for being iridescent in particular Rainbow Moonstone and Labradorite.  The iridescence in gemstones can result in spectacular flashes of colour which are mainly visible as the gemstone is slowly moved in the light and is also known as schiller or labradorescence.