Heat Treatment

Most sapphires available today have been heat treated to improve their color. The different types of heat treatment processes vary in complexity, but the basic idea is to alter the color of the stone by heating it. This treatment can transform worthless stones into gem quality sapphires. Black or brown sapphires (see below) can be transformed into gem quality yellow sapphires.

Sapphires are very common in nature, but beautiful sapphires are not. If there were no heat treated sapphires on the market, gem quality sapphires would be very scarce. Few sapphires come out of the ground with a highly desirable color like cornflower blue (see above). An untreated sapphire will usually command a much higher price than a heat treated sapphire. For instance, a 3 ct. heat treated sapphire would cost about $7200. A comparable untreated Burmese sapphire would cost $14,000. An untreated Kashmir sapphire would cost significantly more. The scarcity of untreated sapphires makes them more desirable in the marketplace.