No two diamonds are exactly the same, which is what makes the process of finding the best diamond both an art and a science. Even though over one billion carats of diamond gemstones have been mined, cut, and polished in the last century, each stone has unique properties that determine the quality of its sparkle, fire, and life.

Ada Diamonds prides itself on sourcing the highest quality 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 or providing you with the best diamond possible. We refuse to sell subpar diamonds. 

To uniformly grade the quality of a diamond gemstone, independent gemological laboratories developed the 4Cs of diamonds in the 1950s:  Cut, Color, Clarity, and Carat Weight. Ada Diamonds adheres to this standardized grading system and all of our diamonds larger than half a carat are objectively graded and certified by globally respected gemologists that grade both mined and lab diamonds.    

The better the cut, color, and clarity, the better the sparkle. The larger the carat weight, the bigger the sparkle. Click on the topics below to learn more.

  • CUT +

    The cut of the diamond is a measure of the quality of the shape, geometry, and finish of a round brilliant diamond gemstone and are graded on a scale from Ideal (the best) to Poor. Ada's gem-cutting partners use bleeding edge equipment, such as robotic laser cutting machines, as well as decades of experience to ensure that Ada's diamonds have optimal brightness, fire, scintillation, and maximum light performance—to ensure that Ada's breathtaking diamonds are a cut above. Learn more about diamond cuts.

  • COLOR +

    A perfect diamond, with no impurities and no defects, is completely colorless. Impurities such as nitrogen decrease the purity of the diamond and cause undesirable yellow or brown tones in the diamond. The color of a diamond 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 near-colorless (G, H, I, J) and refuses to sell any inferior diamonds that are graded as faint-yellow (K, L, M) or worse. Learn more about diamond color.


    Clarity is a measurement of how many blemishes or inclusions are present in the diamond, which can be either micro-defects in the diamond crystal or microscopic foreign particles in 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 Diamonds 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, and larger diamonds tend to be more expensive. When it comes to smaller diamonds, an Ada Concierge may use the term “points” to discuss diamond weights with you. One point is one-hundredth of a carat (0.01). A “33 point diamond” would be one-third of a carat (0.33 carats).


    Ada Diamonds believes that there is a 5th C that a sophisticated consumer should consider when choosing diamonds — Conscience. Ada believes that 21st century diamond purchases should brighten the world, not just the purchaser's world. Learn more about the 5th C.

Independent Certification

Ada's diamonds of larger than 0.5 carats are all graded and certified by independent gemological laboratories. These laboratories are not affiliated with Ada Diamonds in any way, shape or form and grade our diamonds on the same criteria that they grade Earth-extracted diamonds. We work with three laboratories: Gemological Institute of America (GIA), International Gemological Institute (IGI), and Gem Certification and Assurance Lab (GCAL).

Many of Ada's fancy colored diamonds (blues, pinks, yellows) are graded by GIA; however, Ada's colorless diamonds are most commonly graded by IGI. The reason that we do not regularly use GIA for our colorless 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. GIA has stubbornly refused to change it's decision, despite heavy interest from sophisticated consumers. 

1.0ct Ideal cut D color VS1 clarity from IGI

The same diamond as graded by GIA

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 diamond that was first graded by IGI and then by GIA.