Understanding Gemstone Enhancements
Why Treatments Exist – and Why Transparency Matters
When people start looking into gemstones, one question often quickly arises:
‘Is this stone natural?’
This is a valid question – but in the modern gemstone world, the more accurate question is often:
‘Has this gemstone been treated or enhanced?’
The enhancement of gemstones is not unusual. In fact, it has been part of the gemstone trade for centuries. Many of the most beautiful gemstones seen in jewelry today have undergone treatment to improve their appearance or durability.
What matters is not the existence of the enhancement, but how clearly it is disclosed and understood.
What is Gemstone Enhancement?
Gemstone enhancement refers to any process used to improve the appearance, color, clarity or stability of a gemstone.
These treatments range from very traditional methods that have been used for hundreds of years to modern techniques developed through advanced gemological research.
Some enhancements only affect the appearance of the gemstone.
Others can alter its internal structure or long-term stability.
Understanding this difference is important for both collectors and jewelry buyers.
Example of the ruby above is a gemstone from our ruby collection featuring a before and after treatment picture
Traditional and Widely Accepted Treatments
Certain gemstone treatments have been used for so long that they are considered standard practice in the industry.
A well-known example is the use of oil in emeralds.
Emeralds often have natural internal fractures. Filling these tiny cracks with colorless oil helps to reduce their visibility and improve transparency. The oil does not alter the chemical composition of the stone – it merely improves light transmission.
As this treatment has been used for centuries and is reversible, it is generally accepted as long as it is properly disclosed.
Another widely accepted treatment is heat treatment, which is often used on rubies and sapphires. Heating can improve colour and clarity by dissolving certain inclusions within the crystal structure. In many cases, heating simply brings out the stone's natural colour potential.
You can explore examples in our Emerald Collection, where we offer both traditionally treated and untreated stones. Some emeralds naturally display such a harmonious internal structure and transparency that no enhancement is required, allowing their character to shine exactly as nature created it.
Structural Enhancements
Other treatments go a step further and stabilize the gemstone.
For example, some stones can be filled with resins or polymers to reinforce fractures and improve clarity. While this can make the gemstone more visually appealing and structurally stable, it also means that the stone is partially dependent on the filling material.
In these cases, proper disclosure is essential, as the treatment can affect durability, care requirements and long-term maintenance.
High-Temperature and Diffusion Treatments
Some of the most advanced gemstone treatments involve high temperatures and chemical processes.
A well-known example is beryllium diffusion, often used in sapphires. During this process, foreign elements are introduced into the crystal structure at extremely high temperatures, which can permanently alter the gemstone’s color.
Unlike surface treatments, this process changes the gemstone on a deeper structural level. As a result, full transparency about the treatment is especially important for collectors and buyers.
A More Meaningful Approach to Treatments
Instead of simply dividing gemstones into ‘natural’ and ‘treated’, gemologists often ask more nuanced questions:
Does the treatment only improve the appearance or does it also change the structure of the gemstone?
Is the process reversible, stable or permanent?
Could it affect identification, provenance or long-term care?
These questions help to put each gemstone in the right context.
Gemstone Enhancement – a Brief Glossary
Heat treatment
One of the most common gemstone treatments. High temperatures improve colour and clarity, especially in sapphires and rubies.
Oiling (emeralds)
A traditional treatment that uses colourless oil to reduce the visibility of fractures in emeralds.
Resin/polymer filling
Used to stabilise fractures in certain gemstones. Improves clarity and structural integrity, but requires careful disclosure.
Diffusion treatment
A high-temperature process in which chemical elements are introduced into the crystal lattice, permanently altering the colour.
Filling fractures (glass filling)
Commonly used on lower-quality rubies. Glass fills fractures to improve transparency, but significantly compromises durability and value.
Our Approach at Siam Gems Club
At Siam Gems Club, we believe that transparency is the foundation of trust in the world of gemstones.
Many gemstones undergo natural treatments on their journey from the mine to the market. Rather than avoiding this topic, we believe it is important to communicate openly about it.
Whenever known, we clearly indicate treatments in our product descriptions. Common industry practices such as heat treatment are stated directly, and more significant enhancements are always labelled.
In addition, we regularly send selected stones for independent laboratory certification to verify their authenticity and treatments.
Our goal is simple:
We want to ensure that every gemstone comes with the information necessary to fully appreciate it – both as a beautiful object and as a natural product of the earth.
Precision is More Important Than Perfection
The beauty of a gemstone does not disappear because it has been treated.
Enhancements have always been part of the gemstone trade. They allow stones to reveal their color, clarity and brilliance in ways that nature sometimes only hints at.
What really matters is not the absence of treatments – but the clarity of the words used to describe them.
A gemstone remains a gemstone even after treatment. But the seller's responsibility grows with that treatment.
