Iridescence is a property in materials such as minerals and gemstones that creates a display of rainbow-like colors. The iridescence occurs when light reflects from structures within the material. The colors change according to the angle of observation and illumination. Opals are most well known for their iridescence, but it is also seen in other gemstones such as topaz, moonstone, and some pearls. The precious metal titanium also has iridescent qualities.
