This is a solid crystal opal from the Opal mines at Coober Pedy in South Australia which shows Red, Orange, Blue, Purple and Green colours on both sides and the edges of the stone. N5 with a Brightness rating of 4.
If you see an opal on this website that you might like to have as a pendant, please contact Peter to discuss if it is possible with that particular stone.
You also need to state if you wish to have a bail fitted or not. If you do, then you would need to be charged for the cost of metal, silver or gold.