How to Test for Synthetic Sapphires

Examine the sapphire using a jeweler's loupe with 10x magnification. Shine a bright light underneath the stone, then look closely with the jeweler's loupe. If you see small grooves arranged in concentric circular lines inside the stone, you are looking at a synthetic, lab-created sapphire. These circles, called striae, do not occur in natural sapphires. Striae are especially apparent in older synthetic sapphires that were produced in the 1950s and 1960s.

Consult a professional jeweler or gemologist in your area, preferably one who has been certified by a reputable organization, such as the Gemological Institute of America or the American Gem Society. Ask your jeweler to expose the stone to both short-wave and long-wave ultraviolet light. If the stone is synthetic, it will give off a light blue of yellow-green glow, while a natural sapphire will glow red or white. This test requires expertise to conduct; do not attempt to do it at home with a black light.

Hold the sapphire up to an extremely bright natural or artificial light. Examine the stone closely for small bubbles or pockets of air. If you see tiny bubbles in the stone, you are probably looking at a piece of glass. While natural imperfections are part of any stone, bubbles do not occur in genuine or synthetic sapphires.