We are reader-supported. Buying through any red colored link on our site may earn us commissions. Learn More.
“Make sure you buy a certified diamond with a GIA certificate, or an AGS certificate, those are nonprofit testing labs that tell you what you’re buying so there’s no bait and switch going on.” Mark Vadon, Founder of Blue Nile, in a CNN interview.
We do not recommend buying a diamond with a GSI certificate. We’ve found that GSI grading is not only looser than the gold standards (GIA lab), but weaker than the next level down (IGI and HRD) as well. Unfortunately, GSI does not even carry the consistency to purchase a lower graded diamond and adjust the value accordingly. You should only buy diamonds with a GIA certificate from a reputable vendor like Blue Nile or James Allen. You will actually know what you’re getting from a value perspective and you can compare apples to apples. Retailers don’t use inaccurate certificates like GSI in order to give the consumer a better deal; they do it to make more money off of those consumers.
Gemological Science International (GSI) is a recently established for-profit organization. This commercial laboratory has been around for a few years, not decades like other lab organizations. It’s the only major gemological lab to be founded in the 21st century. Unfortunately, they didn’t come to the industry with fresh ideas or innovative technology. They built their business by appealing to big retail chains in the United States, like Jared The Galleria of Jewelry, Kay and Zales. GSI primarily grades diamonds for large chain stores, and their service is usually speedy.
With locations all over the world, GSI provides gemstone identification as well as grading and appraisal services in the fine jewelry industry. Overall, like EGL and IGI certifications, GSI is consistently looser in their grading than GIA.
A GSI report shows the evaluation of a gemstone based on its structure and quality. The scales and measurements are intended to provide a reference point when purchasing.
The 4 C’s of diamonds (Cut, Color, Clarity and Carat) represent their four main components. Each C is graded on a scale to help determine the quality and value of a diamond.
Diamond cut refers to the quality of a diamond’s proportions, angles and symmetrical facets.
GSI designates Cut grade on the following scale:
A diamond is evaluated for how white or colorless it is. The GSI grades diamonds from D to Z: D being the best diamond color and Z containing noticeable brown or yellow tinting. It is difficult for the naked eye to distinguish two diamonds of adjacent color grades, especially ones graded by the GSI. It is best to seek a more reliable certificate, like one from the GIA, and ensure that the diamond looks colorless to the naked eye.
Clarity grade determines how clean a diamond is from inclusions and blemishes. We recommend purchasing a diamond that is eye clean, so inclusions do not interfere with natural light reflection.
Carat is measured in standard fashion across all grading entities, as it is based on weight. A 2 Carat Diamond equals 400 milligrams or 0.4 grams—weighing approximately the same as a quarter of a raisin. A GSI report will disclose the Carat of a diamond, though Cut quality remains the most important of the 4 C’s.
A diamond’s proportions can help determine the quality of the Cut, although it is difficult for someone without diamond expertise to make a judgment based on the measurements provided in a GSI report.
Other details, like symmetry and polish, will also appear on a GSI certification. While these aspects contribute to the beauty of a diamond, the more important factors are the 4 C’s.
Because GSI primarily works with large chain jewelers like Zales and Jared The Galleria of Jewelry, it is difficult to assess how truly objective they are in grading diamonds. While a diamond graded by the GSI will be less expensive than a diamond who achieves the same grades on a GIA scale, the GSI diamond will be worth much less. The inconsistency and looseness in grading make a GSI certified diamond a risky purchase at best.
Advantages of GSI Certification
Disadvantages of GSI Certification
The GSI provides full reports for their diamonds along with:
Overall, we do not recommend buying a diamond that has a GSI certificate. We strongly encourage only buying diamonds that have a GIA certificate. By pursuing a more reliable certificate, you actually know what you are purchasing and you can compare diamonds fairly. Retailers don’t use inaccurate certificates like GSI in order to give the consumer a better deal; they do it to make more money off of those consumers.
If you have questions about lab certifications or want assistance in ensuring you purchase only a high-quality diamond, please don’t hesitate to contact us.
Diamonds Pro helped us pick a diamond, according to our budget and a few other criteria. We ended up buying a loose diamond from James Allen. We felt that we got very good value for money. The diamond was appraised by another jeweler where we live, confirming its characteristics and value. Finally, we had the diamond set in a ring by a local jeweler, and we’re very pleased with the result! Thank you Diamonds Pro 😊…see more
If you’re looking for more information about diamond certificates, cheack out our guide on diamond certification.
Before you buy a diamond, get personal buying advice from industry veterans. We'll help you get the best diamond for the money.
DISCLAIMER: We don't use your email for marketing. Period.
A diamonds’ price is determined primarily by the 4 Cs of the diamond. On the wholesale level, diamond prices are first based on a diamond shape and
When purchasing a diamond engagement ring, it’s important to find the right retailer to purchase it from. Some retailers excel at niche products li
A wide range of 1 carat diamonds exist both in online markets and local diamond jewelry stores. Not only are there significant differences in beauty
Please enter your email address to receive your 25% off coupon code:
Here is your coupon code: GFDSF3GF