Week 2: The 4C’s of Diamond Grading

If you’ve ever wondered what makes a diamond a high-quality option and what are specific things you should be looking out for then you have come to the right place!

This week we’re looking at the 4 C’s of Diamond Quality. The Gemological Institute of America grades diamonds based on the color, clarity, cut, and carat of the diamond. A diamond that ranks high in each of these categories will mean that you are getting a diamond of exceptional quality. Let’s get started!


The first C is fairly straightforward. The best diamonds have an absence of color. The less color in the stone, the more desirable and valuable it is. Most of the differences are impossible to see with the naked eye but they directly impact the quality and the price of the stone, nonetheless.

The industry standard of ranking color is from D to Z, with D being colorless and Z having a light color. The diamonds are graded using a comparison system of comparing diamonds to ones of a known color under precise viewing conditions.


As the name suggest, clarity refers to how clear a diamond is of blemishes and inclusions. Diamonds that are entirely free of these blemishes are extremely rare, and rarity affects the value of a diamond. While no diamond is perfect, they can come close. The GIA Clarity Scale ranks diamond from Flawless to Included, seen below.  

  • Flawless (FL)
  • No inclusions or blemishes are visible to a skilled grader using 10× magnification.
  • Internally Flawless (IF)
  • No inclusions and only blemishes are visible to a skilled grader using 10× magnification.
  • Very, Very Slightly Included (VVS1 and VVS2)
  • Inclusions are difficult for a skilled grader to see under 10× magnification.
  • Very Slightly Included (VS1 and VS2)
  • Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification.
  • Slightly Included (SI1 and SI2)
  • Inclusions are noticeable to a skilled grader under 10x magnification.
  • Included (I1, I2, and I3)
  • Inclusions are obvious under 10× magnification and may affect transparency and brilliance.

Each diamond is unique with their own blemishes and inclusions. The closer to Flawless, the higher the value of the diamond.


Commonly mistaken for the diamond shape, the cut of a diamond refers to its precise proportions and facets, a sign of workmanship. The cut of a diamond influences different factors such as its brilliance and sparkle. Brilliance refers to the amount of light reflected by a diamond; more brilliance equals a gorgeous shine. To grade the cut of a diamond the GIA looks at these 7 components:

  1. Brightness
  2. Fire
  3. Scintillation
  4. Weight Ratio
  5. Durability
  6. Polish
  7. Symmetry

Their grading scale is ranked from Excellent to Poor.


The most commonly known of the 4 C’s, the diamond carat refers to its weight. Generally, a higher carat weight leads to a higher value of the stone. A carat is measured in metric carats, equal to 0.2 grams. A carat can also be referred to in points, as one carat is divided into 100 points so a 200-point diamond will weigh 2 carats.

Also commonly confused for Karats, which refers to the purity in Gold and not diamonds.

The carat system is a fairly simple weight measurement system used for many gemstones.

We hope you learned the basics on how to determine the quality of a diamond! Check back next week for more content, see you soon!