This is a natural rainbow matrix slabs from the andamooka opal fields. This has been treated and the treatment is permanent but bleach and chemicals can dull the colour.

We have listed below how to treat with sugar only but if you like to use acid as the miners do you can find instructions on opal auctions

TREATMENT FOR ANDAMOOKA MATRIX WITH SUGAR ONLY.
MATERIALS-BUT YOU CAN TRY OIL IF YOU LIKE
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. You can also soak in aceton for 10 minutes to dry the stones out.
- 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 500 F 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.
You may have to treat a stone a few times to get the desired result.
Remember to have fun!
WE HAVE TAKEN THE PHOTO WITH THE ROUGH WET.
In the learning section of opal actions there is details on how to treat with acid and sugar but this sugar only gets good results if the material is porous
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