CHARLES D. WINTERS / SCIENCE PHOTO LIBRARY CHARLES D. WINTERS / SCIENCE PHOTO LIBRARY
Opal. Polished opal, a form of hydrous silicon oxide (silica, chemical formula Si.O2). The distinctive sparkling play of colour (iridescence) is typical of precious opals. These bright flashes of colour are caused by light refracting as it passes through the various layers of silica that constitute the opal stone. The finest opals are found in Australia, Wales and Mexico.
Model release not required. Property release not required.