Choose a diamond with a GIA or AGS Diamond Grading Report.  Avoid other Diamond Grading Reports.

​DIAMOND GRADING LAB REPORTS

Diamonds are presented with Diamond Grading Reports, or "certificates", from a variety of laboratories. Consumers must understand that the different laboratories use the same "grades", or grading nomenclature, but apply them with different standards. That is, an "H" color from one laboratory may look whiter, or darker, than an "H" color from another laboratory. A similar difference occurs with clarity grades.


THE STRICT GRADERS: GIA and AGS

We recommend that our customers purchase stones with Diamond Grading Reports from laboratories that are consistently strict in their grading. These are:

• The Gemological Institute of America's Gem Trade Laboratory (GIA).  The GIA is the most widely respected diamond grading laboratory in the world.  They CREATED the diamond color grading and diamond clarity grading scales that have subsequently been utilized by almost every other laboratory in the world.  GIA owns the legal rights to the diamond color and clarity grading scales and grades and the GIA Gem Trade Laboratory issues grading reports based on their original standards.
• The American Gem Society Laboratory (AGS).  The AGS is a highly regarded diamond grading laboratory that was created to provide a "better" diamond grading report than that provided by GIA for what were the better and more ethically minded retail jewelers in the United States.  To their credit the AGS grading of color and clarity is on par with the grading by GIA. The aim for AGS was to provide diamond grading reports with strict color and clarity grades and also to provide more information on and a method for grading the Cut of a diamond.  Until today, AGS has always led GIA in assessing and grading of Diamond Cut and Proportions.

No two diamond grading laboratories will assign exactly the same color and clarity grades for every single diamond that was inspected.  However, it is clear that the GIA and AGS laboratories are very much the equal in their color and clarity grading.  On a small percentage of laboratory reports GIA may be a grade higher and on an equally small percentage AGS may be a grade higher.  There has been no proof of a tendency or a bias of one being more strict or more lenient than the other.  In essence, the grading of color and clarity by GIA and AGS are on par with each other.  However, the AGS diamond grading reports can provide much more comprehensive and detailed information on the Cut and Light Performance of the diamond.

However, it is extremely important to note that just because a diamond comes with a GIA or AGS grading report does not mean that it is a "good" diamond or one that you would want to own.  Many other factors should be involved in your decision including the Cut of the diamond, the presence or absence of diamond fluorescence, the type and location of inclusions, the price of the diamond and much more.

THE OVER GRADERS

In our opinion just about all other Diamond Grading Reports can be classed simply as "inaccurate".  Where this borders on poor ethics and impropriety is that the following laboratories utilize the same color and clarity grading scales created by GIA but assign grades based on completely different standards.  Therefore, a diamond that GIA and AGS would describe as having a color grade of "J" you may find that EGL (European Gem Lab) International may grade as an "F" color.  And a diamond that GIA and AGS would give a clarity grade of "SI1" EGL International may grade "VS1".   The Diamond Grading Laboratories that in our opinion consistently deviate to varying degrees from GIA color and clarity grading standards are listed below.  We suggest that you do not purchase a diamond with a report from any of the following laboratories.  We would also suggest that you avoid any seller that would suggest that you purchase a diamond with a report from any of these laboratories.

• European Gem Lab (EGL) International (formerly known as EGL Israel), aka EGL Gemological Laboratories aka EGL Eurogem

• European Gem Lab (EGL) Antwerp
• European Gem lab (EGL) Asia
• European Gem Lab (EGL) India
• European Gem Lab (EGL) South Africa
• European Gem Lab (EGL) Platinum