Natural Gemstone Treatments & Certification

Understanding What You Are Buying

When purchasing a natural-coloured gemstone, one of the most important things to understand is that natural does not necessarily mean untreated.

A gemstone may have formed naturally within the earth and subsequently undergone treatment to improve its colour, clarity or overall appearance.

This is common within the coloured gemstone industry.

Treatment does not automatically make a gemstone undesirable. Many accepted treatments have been used within the jewellery industry for generations.

What matters is what treatment has been performed, whether it has been properly disclosed and how that treatment affects the gemstone's rarity, durability, care requirements and value.

For significant natural gemstones, an independent laboratory report can be an extremely important part of understanding exactly what you are purchasing.

Natural vs Untreated – What's the Difference?

These terms are sometimes incorrectly used as though they mean the same thing.

They don't.

A natural gemstone is a gemstone that formed naturally within the earth rather than being manufactured in a laboratory.

An untreated natural gemstone is a naturally formed gemstone that has not undergone a detectable treatment intended to alter its appearance.

A treated natural gemstone is still naturally formed but has undergone a process after mining to modify or improve certain characteristics.

For example, both of these sapphires may be natural:

• Natural Sapphire – Heated
• Natural Sapphire – No Indications of Heating

The distinction can be extremely important, particularly with fine-quality gemstones.

Why Are Gemstones Treated?

Natural gemstones are products of nature and rarely emerge from the earth looking exactly as they do in finished jewellery.

They are cut and polished, and many may also undergo treatment.

Treatments can be used to:

• Improve colour
• Improve apparent clarity
• Reduce the visibility of fractures
• Alter or enhance colour
• Improve the overall appearance of a gemstone

Some treatments are considered routine within particular sectors of the gemstone market, while others can have a much greater effect on rarity, durability and value.

That is why proper disclosure is essential.

Heat Treatment

Heating is one of the oldest and most widely accepted treatments used for coloured gemstones.

It is particularly associated with gemstones such as sapphire and ruby.

Controlled heating can alter or improve colour and, in some cases, clarity.

A heated natural sapphire or ruby is still a natural gemstone.

However, a fine natural sapphire or ruby for which a respected laboratory finds no indications of heating may be considerably rarer than a comparable heated stone.

As quality, size and rarity increase, that distinction can become increasingly important to value.

Emerald Clarity Enhancement

Natural emeralds frequently contain fissures that reach the surface of the gemstone.

Oils, resins or other substances may be introduced into these fissures to make them less visible and improve the apparent clarity of the emerald.

Colourless oil has traditionally been used for this purpose.

An enhanced emerald can still be completely natural.

However, the degree of clarity enhancement can be extremely important.

Depending on the laboratory and its terminology, an emerald may be described as showing enhancement such as:

• Minor
• Moderate
• Significant

A fine emerald with little or no clarity enhancement can be considerably rarer than one whose appearance has been substantially improved by filling surface-reaching fissures.

For an important emerald, this is information we believe a customer should know.

Fracture Filling

Fracture filling involves introducing another material into surface-reaching fractures to make them less visible.

One example is glass-filled ruby.

This should not simply be regarded as equivalent to traditional heating.

The quantity and nature of the filling can significantly affect the gemstone's appearance, value, durability and care requirements.

Some heavily filled gemstones can also be sensitive to heat, chemicals and jewellery repair procedures.

For this reason, a customer purchasing a significant ruby should not simply ask:

"Is this a natural ruby?"

The better question is:

"Is it natural, and what treatments have been detected?"

Other Gemstone Treatments

The coloured gemstone market uses a number of additional enhancement techniques.

Depending on the gemstone, these may include processes such as:

Irradiation – used to alter or produce colour in certain gemstones.

Diffusion treatment – a process that can introduce colour-producing elements into or near the surface of a gemstone.

Dyeing – adding colouring substances to change or intensify appearance.

Coating – applying a surface layer to alter colour or appearance.

Impregnation or filling – introducing substances into pores, cavities or fractures.

Not every treatment applies to every gemstone, and different treatments can have very different implications.

This is why the words "treated gemstone" alone don't always tell the complete story.

Permanent vs Less Stable Treatments

Another consideration is the stability of a treatment.

Some treatments are generally considered stable under normal conditions of wear, while others can be affected by heat, chemicals, sunlight or cleaning methods.

This becomes particularly important when jewellery is being:

Cleaned

Repaired

Resized

Reset

Polished

Exposed to heat

A jeweller should ideally know what gemstone is being handled and what treatments it may have received before commencing work.

Proper disclosure therefore matters not only when purchasing a gemstone, but throughout the life of the jewellery.

Gemstone Certification

Why Independent Laboratory Reports Matter

The more important and valuable a natural gemstone becomes, the more important independent verification can become.

A reputable gemological laboratory has specialist equipment and expertise that allows it to investigate questions that may not be reliably answered by visual examination alone.

Depending on the gemstone, laboratory and testing results, an independent report may provide information including:

• Whether the gemstone is natural or laboratory-grown
• Identification of the gemstone
• Weight and measurements
• Colour description
• Whether detectable treatments are present
• Whether indications of heating have been detected
• The degree of clarity enhancement in certain gemstones
• In appropriate cases, an opinion regarding geographic origin

For a significant gemstone, this information can materially affect rarity and value.

A Laboratory Report Is Not a Valuation

This is an important distinction.

An independent gemstone laboratory report generally identifies and describes a gemstone and reports the results of its examination.

A valuation, on the other hand, provides an opinion of monetary value for the gemstone or finished piece of jewellery.

They serve different purposes.

For an important natural gemstone, there can be good reasons to have both.

Which Gemstone Laboratories Are Recognised?

There are several respected gemological laboratories internationally.

Depending on the gemstone, its value and the information required, these may include:

• GIA – Gemological Institute of America
• Gübelin Gem Lab
• SSEF – Swiss Gemmological Institute
• AGL – American Gemological Laboratories

Other reputable laboratories also operate internationally.

Not every gemstone needs to be submitted to one of the world's major laboratories. The appropriate level of documentation should be considered in relation to the gemstone's rarity, value and the claims being made about it.

For a particularly important ruby, sapphire or emerald, however, the choice of laboratory can itself become an important consideration.

What About Geographic Origin?

For certain fine coloured gemstones, geographic origin can influence desirability and market value.

Examples might include sapphires associated with Kashmir, rubies from Myanmar, emeralds from Colombia or other gemstones associated with historically important sources.

But determining geographic origin is complex.

A seller saying, "This is a Colombian emerald" or "This is a Burmese ruby" is not the same as having an independent laboratory provide an origin opinion based on gemological testing.

Even highly respected laboratories may occasionally reach different conclusions because geographic origin determination is an expert opinion based on the available scientific evidence and reference data.

When a substantial premium is being charged because of a claimed origin, we believe appropriate independent laboratory documentation is particularly important.

Certification Doesn't Tell You Everything

A laboratory report is extremely useful, but it should not replace actually assessing the gemstone.

A report cannot tell you whether you personally love the stone.

Two natural sapphires might both be unheated and originate from the same geographic region, yet one may have substantially more attractive colour and appearance.

Two emeralds may have similar laboratory descriptions while looking very different.

Two rubies of similar weight can vary enormously in colour, transparency and beauty.

The laboratory report helps tell you what the gemstone is.

Choosing the right gemstone still requires an assessment of how beautiful it is.

When Should You Request a Laboratory Report?

Not every natural gemstone needs a major international laboratory report.

For a relatively inexpensive amethyst, garnet or aquamarine, for example, the cost of extensive laboratory testing may be disproportionate to the value of the gemstone.

Certification becomes increasingly important when:

The gemstone is particularly valuable.

A premium is being charged because it is untreated.

A particular geographic origin is being claimed.

The treatment status materially affects its value.

The gemstone is unusually rare.

You are purchasing an important ruby, sapphire or emerald.

The seller is making claims that cannot reasonably be confirmed by appearance alone.

As the significance of the gemstone increases, so should the level of documentation be supporting it.

Questions to Ask Before Buying a Significant Natural Gemstone

Before purchasing an important natural coloured gemstone, consider asking:

• Is the gemstone natural or laboratory-grown?
• Has it been treated?
• What treatment has been detected?

Does the treatment affect its durability or care requirements?

Is it being sold at a premium because it is untreated?

Is a particular geographic origin being claimed?

Does an independent laboratory report support those claims?

Which laboratory issued the report?

And finally:

Do I actually love the gemstone?

Because certification is extremely important, but it should support the purchase of a beautiful gemstone — not replace it.

The Dream Diamonds Approach

At Dream Diamonds, we believe in disclosure, transparency and education.

When purchasing a significant natural gemstone, you should understand what you are buying.

The word "natural" alone is not always enough.

We want our customers to understand the gemstone's identity, treatments, rarity and certification so they can make an informed decision.

With more than 40 years of experience in diamonds, gemstones and jewellery manufacturing, we can source individual natural gemstones and help you compare not only their laboratory reports, but also their colour, beauty, rarity and overall quality.

For significant natural gemstones, we can also source stones accompanied by appropriate independent laboratory reports or arrange suitable laboratory testing where required.

Because when you are investing in an exceptional natural gemstone, knowing exactly what you are buying matters.