Today it is virtually impossible to sell diamonds or colored stones, weighing more than 0.50 carats, at auctions or diamond sales, without a certificate. Indeed, the gemstone market is now governed by three fundamental questions:
- What is the material of the stone?
- Is it of natural origin?
- Has it undergone any treatment?
However, other characteristics, other than physical, are relevant and this is precisely what certificates drawn up by independent laboratories are concerned with. One finds in particular the country of origin of the stone and its provenance, two parameters that can influence positively or negatively the value of the stone.
An indispensable and irrevocable certificate
In the precious stones market, the demand from buyers and investors continues to grow and tends to widen the types of stones sought. Thus, size, quality, purity and weight have become paramount criteria in the choice of precious stones and then assume the passage through the laboratory to attest to their value. These certificates represent a form of insurance for the buyer who is convinced that the amount he invests in this stone is well justified. If these certificates become a habit when selling precious stones, the laboratories that wrote them are just as important. For diamonds, buyers tend to prefer Gemological Institute of America (GIA) certificates, one of the three world-renowned gemology laboratories, alongside HRD Antwerp and the International Gemological Institute IGI). Indeed GIA certified diamonds have more potential buyers than any other.
For colored stones such as rubies, sapphires and emeralds, the reputed laboratories are the American Gemological Laboratories (AGL), the Gübelin and the GIA. In any case, if the gemstone is of high weight and of rare quality, it is customary for the stone to be certified in several renowned laboratories in order to establish an accurate diagnosis of the characteristics of the stone. Indeed, each laboratory being independent, certain parameters will vary and will then positively or negatively affect the value of the stone, which is why diamond manufacturers do not hesitate to reposition the stone several times in the laboratory to obtain the best characteristics.
A mandatory technical inspection
The importance of certificates is such that today buyers and potential investors ask to see the certificate before they even see the stone physically. That is why it is essential to know the age of the certificate, which may call into question the value of the stone if it is more than 10 years old, for example. Indeed, the cutting and polishing processes of a diamond or a colored stone evolve over time and new technologies.