Light Opal also known as Milky Opal, is a Solid Opal which shows a play-of-colour within or on a light body tone. Light Opal is capable of displaying any combination of spectral colours such as red, blue, purple and greens.
Crystal Opal is a transparent Solid Opal with bright colours flashing through it. Crystal Opal is called ‘Crystal’ because of its transparency.
To be of any value opal must display natural colour, the more colour in the gemstone the more it is valued.