Ada Diamonds adheres to the internationally accepted criteria to grade the quality of a diamond: the 4Cs of Cut, Color, Clarity, and Carat Weight. The better the cut, color, and clarity, the better the sparkle. The greater the carat weight, the bigger the sparkle. Click on the topics below to learn more.

No two diamonds are exactly the same, which is what makes the process of finding the best diamond both an art and a science. Each stone, mined or lab grown, has unique properties that determine the quality of its sparkle, fire, and life. 

Ada Diamonds prides itself on sourcing the highest quality lab diamonds in the world and we avoid the mediocre diamonds that are sadly sold to many consumers. We don’t expect you to be a diamond expert, and we take seriously the responsibility of providing you with the best option possible. We refuse to sell unexceptional man made diamonds. 

  • CUT

    The cut of the diamond is a measure of the quality of the shape, geometry, and finish of diamond gemstone. Only round brilliant diamonds receive formal cut grades on a scale from Ideal (the best) to Poor. Ada in uncompromising on cut quality to ensure all of our diamonds have optimal brightness, fire, scintillation, and maximum light performance. Learn more about diamond cuts.


    A perfect diamond, with no impurities and no defects, is completely colorless. Impurities such as nitrogen cause undesirable yellow or brown tones in the diamond. Color is graded on a range of letters from D to Z — Ada Diamonds only sells stones are that are independently graded as colorless (D, E, F) or the better half of near-colorless (G, H) and refuses to sell any inferior color diamonds. Learn more about diamond color.


    Clarity is a measurement of how many blemishes or inclusions are present in the diamond, which can be either defects in the diamond crystal or microscopic foreign particles within the diamond. The lower the clarity of a diamond, the more imperfections in the diamond. Clarity is graded on a range from Internally Flawless to Included. Ada only sells diamonds that are Slightly Included or better. Learn more about diamond clarity.


    The carat weight of a diamond is a measurement of its weight. One carat is exactly one-fifth of a gram (0.20 g). When a diamond is properly cut, the carat weight defines the size of the diamond. When it comes to smaller diamonds, an Ada Concierge may use the term “points” to discuss diamond weights with you. One point is 0.01 carats. Thus, a “33 point diamond” would be one-third of a carat (0.33 carats).

Independent Certification

Ada's lab diamonds of larger than 0.5 carats are all graded and certified by independent gemological laboratories. These laboratories are not affiliated with Ada Diamonds and grade our diamonds on the same criteria that they grade Earth-extracted diamonds.  We primarily work with three laboratories: IGI, GCAL, & GIA

  • IGI (International Gemological Institute)

    The majority of diamonds sold by Ada Diamonds are graded by IGI in Manhattan. The IGI Diamond Report is a statement attesting to the authenticity of a diamond and provides a reliable and accurate report of its identity and grade based on an internationally recognized system.

    Each diamond is scientifically analyzed by several gemologists who use their experience in combination with state-of-the-art equipment to produce an accurate description of the characteristics of the diamond and the quality of its cut.

    The grade or quality of a diamond is based on four characteristics commonly referred to as the 4Cs: the Carat weight, Color, Clarity, and Cut. These are analyzed and the results are recorded in the IGI Diamond Report.

  • GCAL (Gem Certification and Assurance Laboratory)

    GCALis a diamond research and identification laboratory specializing in guaranteed diamond grading. GCAL is the diamond geek's preferred grading lab, as every diamond GCAL grades is evaluated by their proprietary Direct Assessment Light Performance analysis. This method analyzes the actual diamond and not a theoretical model, which means every nuance, such as inclusions and transparency, are considered in the grading.

    GCAL proudly offers a Consumer Grading Guarantee that provides cash-back for any error in grading or identification of a certified diamond.

  • GIA (Gemological Institute of America)

    Many of Ada's fancy colored lab diamonds (blues, pinks, yellows) are graded by GIA; however, Ada's colorless lab diamonds are most commonly graded by IGI. The reason that we do not regularly use GIA for our colorless lab diamonds is that over a decade ago GIA made a business decision to not grade as specific as a grading by IGI or GCAL.  GIA will only say that a lab diamond is colorless, not D, E, or F color. GIA will say a diamond is Very, Very Slightly Included, but not VVS1 or VVS2.

    In the past, GIA has produced full specificity grading reports for some of the largest lab grown diamonds ever produced. However, for stones below 5ct, GIA has refused to offer full fidelity grading, despite heavy interest from sophisticated consumers. If a GIA grading is important to you, we are happy to send a diamond of your choice to GIA to have it graded a second time. It normally takes them a few weeks to return the diamond along with their grading report. Above is an example of a lab diamond that was first graded by IGI and then by GIA.

1.0ct Ideal cut D color VS1 clarity from IGI

The same diamond as graded by GIA