An Australian opal triplet is a thin slice of precious natural opal sandwiched between a supporting base and a supporting dome.
It is an opal composite.
The opal used is an opal from Coober Pedy, a vast opal field in the State of South Australia.
It costs a lot less than a solid opal and can last many years without deteriorating.
It is sensitive to water. Do not get it wet or immerse it in water.