Primary Test: High magnification works excellent to identify opals treated by coating and sealing with artificial polymers. Under 10x to 30x the treatment is usually not usually visible since the crackling feature that gives this process away only shows under magnification of at least 60x, and usually requires magnification of 80x to 90x. The polymer material is coated onto and into the opal to hide cracks and fissures, and to impart artificial colors. However, after a short period of time the polymer itself will start to break down and show these tiny cracks and fissures from wear and tear. This is the easiest method of detection for local jewelers and gemologists to use to identify this process. See the images below to review what will normally be found in higher magnification of opals that have been given this treatment.
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. Polymer material can be severely damaged by heat or cleaning.