BOULDER ROUGH OPAL SHOWS GOOD COLOUR. THE PIECE IS 25 X 17 X 15MM. CAN BE USED AS A DISPLAY PIECE. We receive many questions on how we value our rough opal. We value the rough direct from miners and value it at mine cost .The majority of our rough we do not touch in any way ,its direct from mine ,so generally this means we classify rough by eye, so we expect some parcels to cut really good and others that can look promising do not cut well, enerally 60-80% of offerings are priced correctly,10% cuts really good and 10% cuts below ,So good luck in picking the right parcel rough for you.