84.60 CTS FAIRY OPAL ROUGH PARCEL FROM QUEENSLAND [FO48]

FAIRY OPAL ROUGH  
It is precious opal embedded in the natural sandstone and mined in Queensland Australia.Only by carbonizing it does it become like black opal..The treatment is usually oil and sugar with no acid being used.The surface is porous so its hard to get a good finish.
You can polish as a natural stone or coat it with resin to get a better finish.
We suggest a polymer resin as its stable.inert and nontoxic and dosent yellow..
We have also used mono-compontent thermo set resin,cynoacrylates and 2 parts resin but these can turn yellow over time.