Different diamond certificates – what you should know:

Compare certificates from 3 reputable US Diamond Laboratories:

  • GIA = Gemological Institute of America
  • EGL USA = European Gemological Laboratory [USA]
  • AGS = American Gem Society

GIA grading standards are stricter than ‘EGL US’ or AGS and the same diamond will usually receive one color grade and possibly one clarity grade higher from EGL US or AGS than from the GIA.

Learn about difference between EGL and GIA certificates at Ascot Diamonds Atlanta, Dallas, D.C. & New York

1. EGL US and AGS certified diamonds should always be priced lower than GIA equivalent certificates [same weight, cut, color, and clarity] and it would be unethical to represent these 3 laboratory certificates as being equal in value.

2. Diamond laboratories do not guarantee the desirability, brilliance or value of any diamond. Correct value can only be calculated by professionals with market knowledge and the skills necessary to consider the unique characteristics of each diamond.

3. All Diamond Laboratories [including the GIA] certify any diamond submitted for grading irrespective whether the stone is brilliant and desirable or not. There can be a striking difference in the value of 2 diamonds with identical certificate grades.

4. Provided a diamond is valued correctly no harm is done if the stone has a GIA, EGL US or AGS certificate. Establishing the correct value for each stone is key and clearly the primary responsibility of a trustworthy, competent diamond company.

5. Diamond Color Grades:

All three laboratories describe color in these broad categories:

Colorless = D, E, F

Near colorless = G, H, I, J

Distinct color = K to Z

They disagree however on where each color grade should fall on this color spectrum. As a result the identical diamond submitted to the GIA, AGS or EGLUS will rarely get the same color grade.

Color grades are an educated opinion describing the amount of color present in each stone. It is commonly thought that color grade in a diamond is measured by the amount of yellow present in a stone and while this is true for most diamonds, there are many diamonds with core colors that could be brown, blue, green, gray, pink etc.

The GIA typically downgrades diamonds not strictly on a ‘yellow spectrum’ by one or more color grade whereas the other 2 laboratories often consider the absence of yellow a positive element and provide higher color grades for the best examples of these diamonds.

6. Diamond Clarity Grades:

Clarity grades are based on the quantity, size and position of inclusions under 10 x magnification. GIA clarity grades may be one clarity grade stricter than EGL US or AGS, however in our experience it is not unusual for all 3 laboratories to provide identical clarity grades.

Diamonds are the most intriguing and brilliant of all gemstones. Select a company that appreciates cut, clarity and cares about their reputation.

We invite you to visit an Ascot showroom in New York, Dallas, D.C. or Atlanta, where in a professional atmosphere clients enjoy a priceless education and compare diamonds from the most meticulously selected diamond inventory in the world.

Join our email list

You will be the first to know about new exciting designs, events, sweeptakes, and much more.

Please enter a valid email to subscribe

You have been succesfully subscribed to the newsletter, click close to continue.