FAIRY OPAL ROUGH  SLAB 
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  or sugar with no acid being used.This is a parcel that has been treated to show the fire so you can make as specimens or re shape and or cut into smaller stones.If so you will have to re treat.
TREATMENTS
--On the opal field the normal treatment is to wrap the stones in aluminum foil with a some sugar and olive oil and throw into the hot coals for 15 minutes.I have tried this with varying success.
- You can heat the stones in a oven to 100 degress F [38C] for a hour to dry them out
Place gently in a  bowl with syrup of sugar. Heat for 8 hours but not to boiling  as you will loose the water so the sugar seeps in to the stone-i once left for  over a week and had good results.
Wrap in aluminum foil and heat to 400 for 4 hours-you can check earlier. This is best done on a out door bbq,kiln or oven.
-You can treated like Andamooka matrix with acid-details are in the learning section on the site.

TREATMENT FOR FAIRY OPAL AND ANDAMOOKA MATRIX WITH SUGAR ONLY.


MATERIALS
250 grams glucose,white castor sugar,pot or pressure cooker,plastic tweezers.
STEPS
-Pre shape the material

- Thoroughly dry the material in oven sun or hairdryer.
- Put water in pot on low temperature and add glucose and castor sugar. DO NOT BOIL.
-Place warmed stones into warm solution and cover the stone with liquid.
-leave on low temperature for 24 hours but DONT BOIL.
-Remove with tweezers and let cool.Use a paper town to wipe away access.
The next steep is to carbonize the sugar in the stone. Place the stones on a metal or pyrex dish and place in a kiln at 600 degrees for one hour.This will burn or carbonize the sugar in the stone.
_When the stones have cooled clean on a grinding wheel.
Remember to take all precautions with gloves and mask and clothing with good ventilation.
This is a natural product so results may vary a bit due to how porous the sandstone is. Some material will have to be treated a few times to get good results. You can also experiment with various temperatures as i like to cook with lower temperatures.
Remember to have fun!
WE HAVE TAKEN THE PHOTO WITH THE ROUGH WET.
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POLISHING
This parcel 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..Check out our listings of fairy opal polished in sedaopals.Some of there were polished in china under vacume with a amazing finish.
We have also used mono-compontent thermo set resin,cynoacrylates and 2 parts resin but these can turn yellow over time.  ive even heard of nail polished used and hardened under uv lights.
The weight and size is app
It is similar in appearance to Honduran opal.