Heat Treated Gemstones 101: The Essential Guide
Have you ever wondered why some gemstones have vibrant colours while others appear dull? The answer may lie in the process of heat treatment. In this blog post, we will explore what heat treatment is, why it is used, and the most common gemstones that undergo this process.
Everything You Need To Know About Heat Treatment
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 coloured gemstones in the market have undergone heat treatment as a way to improve the stone’s colour—and in cases like sapphire, clarity. Gemstone heat treatment is considered to be a stable, durable, and permanent treatment.
What is Heat Treatment?
Heat treatment is a process commonly used in the gemstone industry to enhance the colour, clarity, and overall appearance of gemstones. This process involves heating the gemstone to high temperatures and then cooling it down slowly to alter its internal structure.
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?
Heat treatment is used for a variety of reasons, including:
- Enhancing the colour of the gemstone
- Improving the clarity by removing or reducing inclusions
- Removing unwanted colour zoning
- Creating a more uniform appearance
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 colour. 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.
Most Common Heat Treated Gemstones
While many gemstones can undergo heat treatment, some of the most common ones include:
Aquamarine
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 colour and produces a prominent blue presence.
Ruby
Heat treatment is often used to improve the color and clarity of rubies. This process can help remove the purplish tint that is commonly found in lower-quality rubies, resulting in a more desirable red hue.
Sapphire
Blue sapphires are frequently heat treated to enhance their color and remove any unwanted brownish tones. This process can transform a dull sapphire into a vibrant blue gemstone.
Topaz
Heat treatment is commonly used on topaz to create vibrant blue colors. Natural topaz is often colourless or pale, but through heat treatment, it can be transformed into stunning blue hues that are highly sought after.
Amethyst
To ensure that radiantly electric purple hue, heating removes the unwanted brownish tint in most natural Amethyst. Heat Treatment also lightens the color of the darker coloured stones. Overall, the heated Amethyst is brighter and more vivid in colour.
*This information discusses heat treated Amethyst in general. Jaiyen Jewellery's Amethysts attain their colour naturally.
Summary
Overall, heat treatment plays a crucial role in the gemstone industry, allowing gem cutters to enhance the beauty of gemstones and make them more appealing to consumers. The next time you admire a dazzling ruby or a brilliant sapphire, remember that heat treatment may have played a part in bringing out its natural beauty.
