Emeralds are commonly treated to enhance their appearance and durability. It's important to understand these treatments when buying or valuing emeralds. Here are some common treatments applied to emeralds:
- Oiling: The most prevalent treatment for emeralds is oiling. This involves filling surface-reaching fractures and cavities with colorless oils or resins. The purpose is to improve the clarity by reducing the visibility of inclusions and enhancing the stone's transparency. Cedar oil and other colorless oils are typically used for this treatment. Oiling is considered an accepted practice in the industry, as long as it is properly disclosed.
- Filling: In addition to oils, emeralds can be treated with fillers to improve clarity and appearance. Resins, polymers, or glass-like substances may be injected into fractures or cavities to fill them. This treatment can enhance the stone's transparency and minimize the visibility of inclusions. However, filled emeralds are typically considered less valuable compared to untreated or minimally treated stones.
- Waxing: Waxing is a temporary treatment used to improve the appearance of emeralds. It involves applying a thin layer of wax or other substances to the surface of the stone. This treatment can enhance the luster and make the emerald appear more vibrant. Waxing is not a permanent treatment and can wear off over time.
- Resin Coating: Some emeralds are coated with a thin layer of resin or similar substances to improve their appearance and durability. This coating can enhance the luster and protect the stone from scratches. However, it is important to note that resin-coated emeralds are not as valuable as untreated or minimally treated stones.
- Heat Treatment: Heat treatment is less commonly applied to emeralds compared to other gemstones. It involves subjecting the emerald to controlled heating to improve its color or clarity. However, this treatment is relatively rare in emeralds, and its use is limited compared to other gemstones like sapphires or rubies.
When purchasing an emerald, it is essential to inquire about any treatments it has undergone and ensure that the seller provides full disclosure. Treated emeralds should be clearly disclosed as such, and the extent and permanence of the treatment should be known. Reputable jewelers and gemological laboratories can provide documentation and information about any treatments applied to the emerald, allowing you to make an informed decision.