Fairy opal stones are natural opals that have been treated.
The opal is formed in porous sandstone in Queensland Australia.
This common opal is light in opal color but when treated by
cooking or additives, the sandstone darkens, and this enhances the reflective
properties of opal.
Fairy stone can be confused with Andamooka treated matrix
which can resemble more cement structure than sandstone base.
Sugar and bake solutions have been used in the past but now
more sophisticated techniques are used for resins like opticon to specialise stabilized