Whether you are buying or selling a diamond, it is important to understand any documentation you have, what it means and how it impacts the value of your stone. Diamond certificates and reports detail the characteristics of a stone and are issued by diamond grading laboratories. These give you greater insight into the quality and therefore value of your diamond, however you do need to take into account which lab issued the certificate or report. Below we answer some of the most common questions we get asked about diamond laboratories.
What is a diamond laboratory?
A gemological laboratory is an independent and unbiased organization that grades diamonds for the trade and the public.
How do diamond laboratories differ?
There are a number of well-known labs in existence with varying degrees of accuracy in their grading standards. Each lab follows its own grading system and sometimes uses its own terminology.
Throughout the diamond industry, the GIA (Gemological Institute of America) is considered the gold standard. Some laboratories have been known to inflate their grades to make a stone seem more desirable, and therefore valuable, than it really is. Its important to know that if your stone has been graded by a non-GIA laboratory, be aware that they could be off by a grade or two.
What are the most popular diamond grading laboratories?
Some of the most popular diamond grading laboratories in the world include:
- GIA
Founded in 1931, the GIA (Gemological Institute of America) is a nonprofit institute and one of the most widely recognized laboratories in the world. Headquartered in California, they are considered the leading laboratory in the diamond industry, with the strictest and most trustworthy grading standards.
- AGS
The AGS (American Gem Society) is known as one of the most reputable diamond laboratories, second only to the GIA. Their pioneering work on cut grades (they were the first laboratory to include it on their grading certificates) and scientific approach to grading has established them as a trusted name in the industry. Unlike the GIA, AGS uses a grading scale of 0-10: 0 is the highest grade and 10 is the lowest.
The EGL (European Gemological Laboratory), while not the most reputable in the world, is a widely used laboratory. They are known for their grading of diamonds under 1ct and are often a popular choice thanks to their low certification costs. The EGL is not known for strict grading’s, and is consistently a few grades below GIA gradings. While some people still accept reports from EGL USA, the consistently poor grading from their European locations have tarnished the company name. Because of this, they are not recommended in today’s market as continue to lose credibility in the diamond marketplace.
Based in Belgium, the IGI (International Gemological Institute) is the most popular gemological laboratory for the major jewelry chains in the US and Canada (Kay, Zales, etc.). This is due to their quick and low cost grading services. However, they have developed a reputation for lenient and inconsistent diamond grading.
- HRD
HRD (Hoge Raad voor Diamant, translated as the “Diamond High Council”) is a lesser-known laboratory in the United States, but very active in the European diamond marketplace. While it is not as accurate as the GIA, it typically only ever differs by a single grade.
Founded in 2000, GCAL (Gem Certification & Assurance Lab) is the only laboratory to guarantee their color and clarity grades. Because of this, they have gained a great reputation for strong grading’s and a quality service, but are still young in the industry.
How does the laboratory that graded my diamond affect its value?
Simply put, it depends on the accuracy of the labs grading’s. If your diamond was graded by the GIA, you can be confident that you know the exact characteristics of your diamond. If your diamond was graded by a different lab, there are likely some discrepancies, meaning that your stone could be of a lower quality.