This is a banded opal form Coober Pedy, which has been cut into a semi-circle shape and polished on both sides. The bands have lots of strong coloured flashes of red, green, orange and blue. Some of the bands go all the way through to the back (see last photo). The base of the stone is 1.8cm long with a thickness of 4mm and a height of 1.1cm. The stone weighs 7.6 carat. It would look lovely set into a chunky pendant or a necklace.