Heated vs. Unheated Sapphires

Are unheated sapphires worth more than heated sapphires? In a lot of cases, unheated sapphires are more valuable, however it is a common misconception that heat treatment decreases the value of a sapphire or that somehow a heated sapphire is always less valuable than an unheated sapphire. In fact, heat treatment is always done to increase the value of a sapphire.

Heat treatment is a widely accepted practice that not only improves color, but also helps dissolve inclusions, improving its clarity. In fact, most sapphires are heat-treated because very few sapphires exist with an ideal color and clarity. Market demand sets the preference, and by a wide margin people prefer to buy a sapphire that has higher clarity and a better color saturation—which is why globally about 95% of all sapphires sold have been heated.

A sapphire’s market value (and therefore price) is driven by its beauty, based primarily on color. A heated sapphire with a brighter, more evenly distributed color may be more valuable than an unheated sapphire with a paler, less saturated color. After color the next most important aspect in setting value is clarity. Once again, heated sapphires will almost always lead here as heating tends to dramatically improve the clarity (and sparkle!) of most sapphires.

The images below are a good example of this. Both images are the same gem–on the right you can see a gorgeous light blue sapphire with a soft hazy appearance. We cut this one without heat treatment as Jeff felt the color and clarity were “good enough” to leave it as is. Alas, the market did not agree—it sat unsold for several years, when most of our sapphires will sell in a year or less. Consequently, he decided to heat the sapphire, and on the right you can see the result—it became a deeper more desirable shade of blue, and the clarity was dramatically improved. Viewed in daylight the difference in sparkle was remarkable. The same gem that sat for several years sold very rapidly after heating, and for a higher price per carat–a perfect example of the market showing what’s truly most valued.

Right now some of you might be saying “Wait, I was told unheated sapphires are more valuable!” That’s only true when certain criteria are met. If you have two identical sapphires—lets say they are both round, one carat, with excellent clarity and a gorgeous rich blue color—then the unheated one most certainly will be more valuable, becuase it is much more rare. The problem is that very few unheated sapphires have the best color or clarity—upwards of 90% of the time they are pale, cloudy, or both–and that means they are worth less than a clear rich blue heated gem.

The changes in color and clarity made by heating sapphires is permanent and stable. In every case its done to increase the final value of the gem relative to the unheated rough or gem. Choosing the right gemstone for you is deeply rooted in your personal preference. Whether you prefer a heated or unheated sapphire, we are here to help you find a gem that is perfect for you.