So you come across your favorite gemstone jewelry and two words catch your eye—heat treated. Questions come to mind: What does that mean? Does it affect the quality of my gem? Does this mean my gemstone isn’t natural?

In fact, most colored gemstones in the market have undergone heat treatment as a way to improve the stone’s color—and in cases like sapphire, clarity. Gemstone heat treatment is considered to be a stable, durable, and permanent treatment. In this post, we will answer all of your questions regarding heat treated gemstones.



Heat Treatment is a gemstone’s exposure to high temperatures that alters the color and increases the clarity. Specifically, heating is used to lighten, darken or enrich the color. Without heat treated gemstones, fine gems’ availability in the most desirable colors would be scarce. The price of the gemstone would also significantly increase.

Enhanced vs. Natural Gemstones

Heat is one of the forming conditions of a gemstone. This can occur within the ground or artificially. If the heat occurs while the gemstone is in the ground, it is not enhanced. However, if the gem undergoes heat treatment after being mined, it’s an enhancement.

Natural gemstones form within the earth. Stones such as Moonstone and Rose Quartz are typically not treated. However, some natural stones—like Amethyst, Topaz, Citrine, Sapphire, Ruby, Aquamarine, and Tanzanite—are usually heated after they’re recovered from the earth.

Why Is Heat Treatment Used?

Gemstone enhancements—such as heat treatment—improve the gems’ wearability and appearance. The treatment is chosen based on the gem type and desired effect.

What Is Radiation?

Although the term radiation seems terrifying, it’s simply another replication of a natural process. In a natural setting, benign radioactive elements impact many gemstones during formation.

Radiation in a facility modifies the electron sharing between crystal structures. This is usually followed by heating the gemstone to maintain the ideal color. Blue Topaz is one of the most well-known gemstones that's radiated. This is to bring out its brilliant blue hues in a deeper saturation.



Now that we’ve covered the ins-and-outs of heat treatment, let’s dive into the specific types of gemstones that undergo heat treatment and radiation.


The Aquamarine is surprisingly one of the most common heat treated gemstones. Its natural form takes on more of a green tint. If the Aquamarine does not heat underground, enhanced treatment is the next best option. Heat in a controlled environment removes the greenish color and produces a prominent blue presence.