Clarity enhancement
Coloured oil introduced in the fissure of a gemstone does not only improve its clarity but also its colour. The coloured oil contributes to a clear change of the original colour and will be reported as a dyed gemstone.
Colourless oil is applied to all kind of gemstones, regularly while in its rough state, before cutting and faceting has taken place. Unheated faceted stones are also commonly found with traces of oil. This is especially true (but not limited to) for gemstones of a lesser quality with surface reaching fissures.
The vast majority of emeralds are being clarity enhanced either with oil, wax or resin. Oil has been used for centuries to improve the clarity of this variety of Beryl. A more modern enhancement technique involves the use of resins, either natural or artificial, but irrespective of the nature of the filling product (oil, wax or resin), the result amounts to the same: An improvement of the clarity of the emerald.
Because of the prevalence of such a treatment in emeralds, a special scale that takes into account the extent of the clarity enhancement is being used by most laboratories, although there may be some slight variation in wording between them. That scale normally ranges from no indications to indications of significant clarity enhancement.
Oil VS Resin issue
This issue has been rocking the trade for many years and a lot of misconception and false truths are still being passed to the final client.
Many in the trade are under the impression that a filling with oil is superior and more acceptable than a filling with resin. This is mostly due to the fact that oil has been the traditional way to enhance the clarity of emeralds while resins both natural (Canada Basalm) and artificially made Epoxy resins (with polymers used as adhesives) are relatively new comers compared to the former. Both types of product fulfil the same inherent function: Improving the clarity and transparency of the emerald by concealing existing fissures.Oil is not superior to resin in this regard. Oil will tend to thin out faster upon heating or pressure and a resin treatment is normally more stable and requires less servicing (re-treatment) over the years. For these reasons, we do not, as a standard practice, disclose the nature of the filling material present within the fissures of the stone. This may however be stated as a footnote upon specific request of the client.
Most of resins treatments are well accepted in the trade and one of them referred to as “Permasafe” has been used extensively in the past years. With this Epoxy resin treatment, very large seems and surface cavities can sometimes be found at the surface of emeralds. Those filled surface features are easily detected by Gem Testing Laboratories and usually described in the Identification Report. In the presence of such filled seems and cavities, the sentence “Indications of filled fissures and cavities” will be stated on our Reports.Oli Vs Resign Issue
