This is a Yowah Conglomerate Opal from the Yowah Opal fields of Queensland, Australia. Once drilled and fitted with a bail, it would make a very nice pendant. This can be done at a small additional cost. It shows Blue Opal set in brown ironstone.
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.