Non-certified or cheap diamonds are not always good deals. Diamonds treated with different techniques to enhance their clarity and colour as well as synthetic diamonds sold as being natural, are very common in the marketplace nowadays.
Unfortunate gemmologists and clients, dazzled by a tempting price, believe they have found a good deal and do not realise that an apparently beautiful diamond has hidden secrets!
Treated gemstones are generally sold without a gemmological certificate, but it is the retailer responsibility to make the client aware of the treatments the diamond has gone through.
It would be hard to sell diamonds with dark inclusions (such as magnetic pyrites or magnetite). In order to make those gems more appealing, various treatments are used.
Through laser drilling treatments it is possible to pierce a diamond to remove the inclusions, then the drill holes are then filled with wax or synthetic resin with a refraction similar to diamond, thus noticeable only by an expert.
The technique developed by Israeli Zvi Yehuda uses high temperature and high pressure silicone oil to fill the fractures and to make the inclusions less visible.
Through a magnifying lens, it is possible but not easy to find traces of the filling treatments.
Other treatments alter the colour of a diamond through the use of specific autoclaves that reach high tempera tures and high pressures and improve the diamond colour grade.
These treatments, though very difficult to identify, are described in the certificates issued by leading gemmological institutes.
Last but not least we must mention the synthetic diamonds that flooded the European marketplace in recent years and that have now fortunately been flagged up. In this case, we are not talking about common fakes, called in jargon “cubic zirconia”, but diamonds that so-called “we buy gold” stores would buy as real diamonds believing to pay the right price for them.
All enhanced diamonds should have considerably lower market prices compared to normal quotations. The best way to avoid the risk of running into one of these diamonds is to request its gemmological certificate, over and above the common guarantee certificate issued by the retailer in which just the word “diamond” is specified .
Our laboratory’s aim is to identify all these treatments. We steer clear of offering this kind of merchandise.