Primary Test: The diagnostic test for this material is the immersion cell. This is a coating put on these colorless gemstones that imparts the various rainbow colors you see below. The problem is that the coating is usually very fragile and in even a cursory immersion cell made of a plastic Dixie cup and tap water the coating is visible. The reason is that the coating has a strong tendency to flake off during the setting process and during normal wear and tear.
Secondary Tests: The colors of the mystic topaz will be the secondary test. Anyone with even a basic understanding of natural topaz colors will quickly identify these stones to be artificially colored. However, consumers are not so informed and aware of this fact, to the point that we have had consumers contact the ISG office asking about the “location of the Mystic Topaz mine?” Obviously some very creative marketing has gone into this material and care should be taken to inform consumers as to the true nature of this stone before any work is done on any jewelry item as scratches and dings in the color coating are very very likely.
Repair and Setting: EXTREME CAUTION should be used when handling all mystic topaz. The coating of these stones is extremely fragile and subject to scratching almost by just looking at it, not counting actually trying to set one. Pulling prongs or setting prongs will most likely cause scratches wherever the prong or tools come into contact with the stone. Also, be aware that no cleaning should be attempted with the mystic topaz. Below you see the result of one stone before and after a cursory cleaning in a normal ultrasonic cleaner.