Why emeralds are clarity enhanced
Natural emerald commonly contains fissures. When a fissure reaches the surface, a transparent liquid or resin can penetrate it and reduce the difference in refractive appearance between the fracture and surrounding emerald, making the fissure less visible.
This is primarily clarity enhancement: it changes the visibility of existing fractures rather than turning included material into physically flawless emerald.
GIA recognises clarity enhancement as an important consideration in emerald evaluation and reports detectable treatment. GIA Emerald Buyer's Guide
Oil, wax and resin
GIA expanded its emerald reporting service in December 2024 to offer optional identification of filler type. Its current categories include:
| GIA filler result | Meaning |
|---|---|
| Type A | May include oil, wax and/or natural resin |
| Type B | Artificial resin |
| Unidentified | Clarity-enhancing material is present but cannot currently be identified |
Minor, moderate and significant enhancement
The amount or degree of clarity enhancement is separate from identifying the filler itself.
GIA's F1/F2/F3 terminology corresponds to:
- F1 — minor clarity enhancement
- F2 — moderate clarity enhancement
- F3 — significant clarity enhancement
GIA explains that minor enhancement has only a slight effect on face-up appearance, whereas significant enhancement has an obvious effect. GIA FAQ
Laboratories can use different report terminology, so product descriptions should reproduce the wording of the actual report rather than convert every result into a home-made scale.
Are Nigerian emeralds usually untreated?
There is currently no sufficiently robust published dataset to make that claim for Nigerian emerald as a whole.
The correct approach is:
stone-specific evidence > assumptions based on country.
If a Nigerian emerald has not been tested, list:
Treatment: not independently tested
rather than:
Treatment: none
Those statements mean very different things.
Can rough be assumed untreated?
Rough is generally evaluated before the post-cut clarity-enhancement decisions that dominate commercial emerald treatment. GIA's reporting from Jaipur notes that clarity treatment is typically considered after cutting, while cutters planning rough must already think ahead about fractures and the eventual treatment decision. GIA, Jaipur Emerald Cutting
Nevertheless, do not use the appearance of rough as evidence that a later finished stone is “no oil”. Record treatment status again after cutting and before sale.
Why enhancement changes value
Two visually similar emeralds can have different treatment histories. Professional rough buyers consider the potential extent of future fracture filling because treatment level can affect commercial value. GIA, Gemfields Auctions
This does not mean treated emerald is “fake”. A natural emerald remains a natural emerald when its fissures are clarity enhanced, provided the treatment is accurately disclosed.
Recommended product disclosure
A NigerianEmeralds.com listing should show one of the following, using actual evidence:
Treatment: No indications of clarity enhancement — laboratory report
Treatment: Minor clarity enhancement — laboratory report
Treatment: Moderate clarity enhancement — laboratory report
Treatment: Significant clarity enhancement — laboratory report
Treatment: Not independently tested
Avoid “untreated”, “no oil” or “natural clarity” unless the evidence supports the statement.
Care and permanence
Some fillers can be removed, altered or replaced over time; GIA specifically notes that this variability was one reason filler reporting has evolved. GIA, Emerald Report Enhancement
Buyers should therefore keep the laboratory report with the gemstone and inform a jeweller or repairer that the stone is emerald and may contain clarity enhancement before cleaning or repair.