Enhancing Nature: Precious Gemstone Treatments for Sapphires, Rubies & Emeralds

Treated Precious Gemstones

Most gemstones undergo some form of treatment, and this practice is particularly common among precious stones like sapphires, rubies, and emeralds. While these gemstones are naturally beautiful, treatments are often applied to enhance their color, clarity, and overall appearance, making them more desirable in the market. Additionally, treatments can improve a stone’s durability and structural integrity, which is especially important for gemstones that are prone to inclusions or fractures.

Understanding these treatments is crucial for both buyers and collectors, as they significantly influence a gemstone’s value, authenticity, and long-term care requirements.

Although treated, these gemstones are naturally formed through geological processes within the Earth and should not be confused with synthetic or lab-created stones. Synthetic or lab-created stones are man-made and mimic the appearance and properties of natural gems, but they do not occur naturally. Despite having similar chemical compositions and physical properties to natural gemstones, synthetic or lab-created stones are significantly less valuable due to their lack of rarity and the fact that they are produced artificially.

UnTreated Precious Gemstones

Although most gemstones are treated, there are natural gemstones that are not treated at all, and they are highly sought after for their rarity and natural beauty. The occurrence of untreated gemstones largely depends on the type of stone and the quality of the crystal found in nature.

UNTREATED SAPPHIRES
While most sapphires are heat-treated to enhance color and clarity, some high-quality sapphires possess excellent color and clarity naturally and do not require any treatment. Untreated sapphires with rich color (like deep blue, padparadscha, or pink) are highly valuable and rare.

UNTREATED RUBIES
Similar to sapphires, most rubies are heat-treated to improve their color and clarity. However, high-quality rubies from certain regions, like Myanmar (Burma), can be found in a natural state with excellent red color and minimal inclusions. These untreated rubies are rare and command premium prices in the market.

UNTREATED EMERALDS
While nearly all emeralds are treated with oils or resins to fill fractures, some top-quality emeralds, especially from Colombia, do not require any treatment due to their exceptional natural clarity and vivid green color. Such untreated emeralds are exceedingly rare and highly prized

Treatment Type	Description	Sapphires	Rubies	Emeralds	Impact on Price
Heat Treatment	Improves color and clarity. High or low heat (up to 1800°C) may be used to enhance saturation, remove gray, or reduce inclusions.	Most common and accepted. Used to enhance blue color and improve clarity.	Widely used. Enhances red color and may heal fractures with flux residue.	Less commonly used due to delicate crystal structure.	Generally increases price. Especially for sapphires and rubies. Highly accepted in the industry.
Fracture Filling	Improves clarity by filling cracks and fractures with materials like glass, oils, or resins. Often masks internal flaws.	Less common; occasionally treated with glass to improve appearance.	Very frequent. Lead-glass is commonly used to dramatically improve clarity and fill surface-reaching fractures.	Standard practice. Filled with cedarwood oil or synthetic resins to hide fissures.	Usually lowers value. Considered less stable and may require re-treatment. Often viewed as a less desirable method.
Diffusion Treatment	Alters or enhances surface color by introducing elements (like beryllium or titanium) during high heat.	Used to create vivid colors like orange and padparadscha. Color is often shallow and surface-based.	Rarely applied. When used, may involve chromium diffusion to intensify red tone.	Not used due to structural fragility.	Usually reduces price. Market sees diffusion as less valuable due to superficial effect and alteration of natural traits.
Oiling & Resin Treatment	Enhances clarity by filling fractures with natural oils (like cedarwood) or synthetic resins such as Opticon.	Rarely oiled or resin-filled.	Sometimes used, but far less common than glass-filled rubies.	Most traditional and accepted method. Helps improve transparency in visibly included stones.	Accepted in emeralds if disclosed. Resin-filled stones may be valued lower than those only oiled. Stability is a concern with some resins.
Lattice Diffusion & Surface Coating	Alters color by changing the gemstone's crystal lattice or by applying a color coating to the surface.	Lattice diffusion may create deep blues; coatings are less durable and less accepted.	Rarely used. Coating and diffusion seen as less authentic enhancements.	Not applied due to high fragility.	Often reduces price. Treated color is less durable and not deeply integrated into the gem, affecting value and consumer trust.
Bleaching	Removes unwanted brownish or yellowish tones. Often followed by oiling to restore luster.	Rare and generally unnecessary.	Rarely used. Sometimes applied to remove brownish overtones.	Occasionally used to reduce yellowish or brown undertones before oiling.	Must be disclosed. Can slightly lower value if it significantly alters the stone’s appearance or stability.
Laser Treatment	Removes dark inclusions by drilling with a laser, often followed by fracture filling with glass or resin.	Not typically used.	Rare. Used to remove prominent inclusions and improve clarity; often followed by glass filling.	Not suitable. Emeralds are too fragile for laser procedures.	May lower value, especially if considered invasive. Can affect durability and long-term aesthetics.

HEAT TREAMENT
Pale sapphires that were once discarded in the mining process
were treated to a desirable color of blue when heated in a controlled environment.
GIA: https://www.gia.edu/gem-treatment

FRACTURE FILLING
Surface reaching fractures in rubies,such as these,
can be filled with molten lead glass,
lessening the appearance of the fractures.
GIA: https://www.gia.edu/gem-treatment

OILING AND RESIN TREATMENT
Surface reaching fractures in emeralds, such as this one
can be filled with artificial resins, wax, and epoxy polymers.
This lessens the appearance of the fractures,
as the treated emerald on the right shows.
GIA: https://www.gia.edu/gem-treatment

BLEACHING
Jadeite show the material as it looks before and after bleaching.
GIA: https://www.gia.edu/gem-treatment

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