Which gemstones are subject to certification?
When, with great joy and anticipation, we finally buy a piece of jewelry with a colored gemstone or diamond, we always wonder if the stone matches its characteristics. Does this diamond really weigh 1 carat, as the seller said?
There is a certificate to prove the origin and quality characteristics of diamonds and colored gemstones. This article tells you what certificates are provided for which stones and which laboratories you can trust.
Two groups of stones subject to certification:
Diamonds and colored gemstones
What is the best certificate for Diamonds ?
The GIA (Gemological Institute of America) is a non-profit organization that develops and implements quality standards for diamonds and is rightfully considered the most reputable gemological laboratory in the world. They provide the best certifications for any diamond. It was the GIA that created the diamond grading system, on the basis of which national standards have been developed around the world.
As a result of the examination of each diamond, GIA experts get the exact geometric parameters of the stone, assess the quality of cutting and polishing, its color and clarity, as well as the presence of fluorescence.
If your diamond jewelry was provided with a certificate from GIA, you can be sure of its origin and the characteristics described in the certificate.
It is worth mentioning that the price of a diamond at the Rapaport price list is also influenced by the company that issued the certificate. As a rule, AGSL-certified diamonds are sold at a considerable discount from the Rapaport price list because their color and clarity scales are lower than those of GIA, HRD and IGI. That is, AGSL "overestimate" the characteristics of the stone, so diamonds with certificates from these laboratories get lower color and clarity characteristics when they are evaluated by the GIA, HRD or IGI, which consequently affects their price.
What is the best certificate for colored gemstones ?
For colored gemstones we distinguished three of the most reputable: GRS, SSEF and Gubeline.
1) GEMRESEARCH SWISSLAB Gemological Research Center (GRS)
Gemological reports issued by the certification laboratories of GRS Gemresearch Swisslab AG are some of the most authoritative supporting documents for commercial transactions with high-grade gemstones.
Gemological services in the list of GRS works include diagnosis of a jewelry stone, nature of origin, methods of enhancement, for some gemstones the definition of region of origin is provided, as well as characterization of belonging of some jewelry stones to higher quality groups, such as "PIGEON BLOOD" and "SCARLET" for rubies, "ROYAL BLUE" and "CORNFLOWER" for sapphires, "OLD MINE / MUZO GREEN APPENDIX" for emeralds, "SUNRISE" and "SUNSET" for padparadscha, "HONEY-COLOR" for chrysoberyl, "PARAIBA-COLOR" and "NEON-COLOR" for tourmaline-elbaite.
2) One of the leading authorities in the field of colored gemstone authentication is the Gübelin Gem Lab.
Its main specialty is the origin of stones, which can be determined by their unique visual characteristics. Gubelin's gemstone rating takes into account three factors: quality, rarity and importance, where quality is the most important factor. It marks visual aspects such as color, clarity/transparency and shape. Rarity evaluates the type of gemstone, its weight, and any treatments used to enhance the gemstone. Clarity, transparency, and shape describe the uniqueness of the gemstone and its ability to stand out.
3) Another reputable gem certification center is the Swiss Gemological Institute, or SSEF (Schweizerische Stiftung für Edelstein-Forschung).
All gemologists who work in the laboratory have a scientific degree and a special gemological education, have great experience and a high level of knowledge.
The laboratory is equipped with the most modern analytical equipment. This guarantees that the authenticity of gemstones, their provenance and possible processing can be verified using scientific methods of analysis.
The laboratory offers its services to both private and corporate clients. Because the laboratory's analytical results are reliable and its experts are independent, it has received international recognition.
What is in the certificate?
The results of the analysis and evaluation of natural diamonds, synthetic diamonds, colored gemstones and pearls are accompanied by a separate type of GIA certificate.
Diamond Grading Report is the main type of GIA certificate that contains a 4C grade (carat grade, color grade, clarity grade, cut grade) diagram of clarity characteristics and a graphic representation of the proportions of the stone. This report includes diamonds of 0.15 carats and above:
D-Z color natural diamonds - Natural Diamond Grading Report,
Natural Colored Diamonds - Colored Diamond Grading Report, Artificial Diamonds - Laboratory-Grown Diamond Grading Report.For natural colored diamonds, there is a certificate that specifies the origin and structure of the color.
The GIA provides three types of certificates for colored gemstones and pearls:
Identification Report - for colored stones and pearls,
Identification and Origin Report - for colored stones,
Identification and Classification Report - for pearls.
The Identification and Origin Report is available only for rubies, sapphires, emeralds, Paraiba tourmalines, red spinels and alexandrites.
How to avoid counterfeiting?
One of the most important documents for any gemstone (diamond, ruby, emerald, or sapphire) is its certificate. It is true that its presence, especially if it is issued by a prestigious gemological laboratory, may slightly increase the price of the crystal, but it also reduces the risk of being cheated, so the buyers who want to be sure of the quality and authenticity of their sparkling gems order certificates from reputable laboratories (GIA, GRS, SSEF, Gubelin etc.) first of all. The certificate has several degrees of protection, such as micro-printing, watermarks, holographic image. You can check the conformity of the certificate by entering its number on the official GIA, GRS, SSEF and Gubeline website.
A certificate from a world-renowned laboratory for a diamond, ruby, emerald or any other stone not only confirms the characteristics of the stone, but also shows the buyer that the seller is ready to do business openly.
Certifications of which laboratories does Kantor Jewelry provide?
Kantor Jewelry works exclusively with reliable and reputable laboratories of world renown (GIA, GRS, Gubelin, SSEF, GFCO, AIGS, LOTUS).
When it comes to diamonds we work only with natural white and color diamonds certified by the independent Gemological Institute of America (GIA). This organization evaluates gemstones and sets strict international quality standards for the industry.
The GIA certificate number is engraved on the diamond, written on the paper certificate and can be found on the laboratory's global database. Using a magnifying glass, you can check the number on the stone against the documents. This is a guarantee of the quality and authenticity of your diamond.