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四月 2017

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Gem Labs: A Guide to Diamond Authentication

Before the advent of gem labs in the diamond industry, there was more inconsistency and confusion as to the value and rarity of diamonds. Today, gem labs, with their standardized grading systems and certifications for diamonds and other gems, help both retailers and consumers understand the true value of the stone. As a result, the gap between buyer and seller is bridged, creating trust. And when it comes to the diamond and jewelry trade, trust is critical to improving sales.

GIA: The Gem Lab Behind the 4Cs

There are many different gem labs around the world, and they differ from one another in their grading methods, and the services they offer. One of the most well-known gem labs is the Gemological Institute of America (GIA). The GIA is a non-profit organization whose main purpose is diamond and gem research and education. Among GIA’s services are gem assessment and certification through their lab services, as well as ongoing research and gemologist training and certification. The GIA are the creators of the 4Cs of valuating a diamond, based on color, clarity, cut and carat. In addition, in 2005 the GIA introduced a cut grading system that helped create the standard for diamond and gemstone grading throughout the world. This ultimately led to an increase in consistency and uniformity of gem grading across numerous gem labs. The GIA cut grading system is the most widely used and accepted of all systems by gem labs worldwide. The GIA cut grading system includes five grades, from Excellent, Very Good, and Good, to Fair and Poor. Some of the features assessed in the grading process include brilliance, scintillation, weight ratio, symmetry, durability, nicks, scratches, chips and more.

The American Gem Society (AGS) was founded by Robert M. Shipley in 1934, and is a trade association made up of retail jewelers, independent appraisers, suppliers, and selected industry members. The Society trains and certifies jewelers, gemologists, and jewelry appraisers. The AGS laboratories, known as AGSL, were founded in 1996. The AGS gem lab created its own diamond grading scale, including standards for cut, color and clarity.

As opposed to the GIA grading system, which employs an alphabetic rating system, the AGSL uses a numeric grading scale of 0-10, with 0 scoring highest and 10 lowest. Rather than assess all features first, the AGSL system assigns a grade to each factor of the diamond, the color, clarity and cut, to achieve the overall diamond grade. For instance, a diamond with three scores of 0 would be the highest rated diamond available for purchase.

Authenticating All Types of Gemstones

American Gemological Labs (AGL), founded in 1977, is one of the most well-known gem labs when it comes to origin and colored stone gem identification and quality. In addition to stone grading and assessment, the AGL services also include gemstone reporting, gemological research and consumer protection initiatives. They also provide complete colored stone analysis documents specifically for gems of unique importance.

Established in 1975, the International Gemological Institute (IGI) is headquartered in Antwerp, but has offices located globally. IGI comprises one of the largest gem labs in the world, as well as a gemology school. The IGI’s labs in different countries use slightly different grading criteria. IGI’s main customer base includes jewelers, retail chains, insurance companies and accounting and securities firms, as well as private consumers.

The European Gemological Laboratory (EGL) has multiple offices throughout the world, including Paris, London, Tel Aviv, Tokyo and Johannesburg. One of the specialties of EGL as opposed to other gem labs is their grading techniques for gems under one carat weight. In addition, while the EGL uses the GIA diamond grading scale, they have added an intermediate grade to their scale, known as SI3. The SI3 grade was originally used as an in-between grade for diamonds with better characteristics than I3 diamonds, thereby differentiating them from other included diamonds.  Many gem labs do not recognize the additional SI3 grading. Most other labs would actually grade an EGL SI3 diamond as I1, and it would therefore be lower in value.

Diamond certification from a gem lab in combination with the use of interactive, friendly diamond display technology, such as the Sarine Profile, can help build confidence among diamond buyers that they are indeed receiving what they pay for.


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