Primary Test: Composite opals have been on the market for decades. The process is simply to take thin, otherwise unsalable pieces of opal and place them between a clear quartz top and a black onyx bottom plate. The result is what appears to be a very fine quality opal. The finished product is both beautiful and affordable, and is very viable on the market as long as it is properly represented to the consumer as to the structure of the gemstone. This should be an easy identification since viewing it on its side as seen below will easily reveal the various layers which may include 2 or 3 layering depending on the composite process used.
Secondary Tests: None required.
Repair and Setting: Same care should be taken as would be with a natural opal. No heat, no ultrasonic and no cleaners.