Nov 16, 2020
Opalescence and Play-of-Colour Opal is often found to have a milky luster (how the light reacts with the surface). This milky luster is known as Opalescence. However, some opals have bright rainbow colours that appear as flashes when the opal or a light source is moved. These bright colours are known as play-of-colour and are seen on ‘Precious Opal’. Play-of-colour areas of an opal have microscopic silica spheres (which vary in size and arrangement) which diffract light as the rainbow colours. ~SA Image: http://bit.ly/1WyWdXF by Daniel Makes
