What treatment is commonly used to enhance the color of gemstones?

Heating is a widely recognized method for enhancing the color of gemstones, particularly in natural stones like sapphires, rubies, and amethysts. When gemstones are heated, the process can alter their chemical composition and improve their clarity and color. For example, heating can help to dissolve impurities or create new color zones, resulting in a more vibrant appearance.

This treatment is generally permanent, as it is a part of the gemstone's internal structure rather than an external application. It can also sometimes reveal color zoning or intensify the existing hues, making it one of the preferred methods of enhancement in the gemstone industry. Consequently, many gemstones that are marketed today are heat-treated to enhance their visual appeal before being sold to consumers.

Other treatments, while they may also improve the appearance of gemstones, do not typically result in the same level of color enhancement or permanence as heating does, which is why heating stands out as the most common technique used for this purpose.