The 4 CS

The Four “Cs” of Diamond Quality


Of the four Cs, cut is perhaps the most important factor affecting a diamond’s overall quality and beauty. A diamond’s brightness, or its brilliance, is determined by how much light is reflected back to your eyes.



The measurement and comparison of diamond color ranges from colorless to slightly tint. However, discerning the subtle differences between sequential color grades can be almost impossible with the naked eye. For this reason, a letter scale, such as the GIA professional color scale which ranges from D to Z, was created to assist in distinguishing a diamond’s color grade. Diamonds that are in the “D-F” range are considered colorless.


Do You Know Why The Diamond Grading Scale Starts at D?

What Happened to A, B, C?

If you have ever shopped for an engagement ring, you end up learning a lot about diamonds and specifically color. You may wonder why the diamond color grading scale starts at D instead of starting at A but maybe you felt like it was a dumb question. It is actually a very valid question with a pretty straightforward answer.

A long time ago color grading did start with A and in fact, people in the industry graded diamonds with Roman Numerals and with numbers, i.e. I, II, III or 1, 2, 3. Some individuals even described diamond color with double letters such as AA or BB. There was no set standard and these descriptions were used loosely. A better system had to be established and GIA came along in 1953 to set some new rules.

When GIA came up with what is now the industry accepted standard for color grading, they decided to start with a letter that had not been used previously. Since A, B, and C were all used inaccurately in the past, GIA decided to start fresh with the letter D and the scale goes all the way up to Z.

D refers to the absence of color in a diamond and you should think of D as the IDEAL! This means that the diamond is white or colorless.



A carat is a unit of measure for diamonds, where one carat equals 100 points, or 0.2 grams. This measurement is referred to as the carat weight and is used to determine a diamond’s size. Larger diamonds are rarer and therefore more highly valued.



Clarity describes the presence of imperfections both on and within a diamond.

Essentially, the clarity grade describes the flawlessness of a diamond; the fewer the imperfections, the higher the clarity grading.

  • FL/IF
    – Flawless or Internally Flawless.
  • VVS1/VVS2
    – Very, Very Small Inclusions. Requires 60X magnification to clearly see inclusions.
  • VS1/VS2
    – Very Small Inclusions. Requires 30X magnification to clearly see inclusions. A good choice for those wishing to balance quality and affordability.
  • SI1/SI2
    – Small Inclusions. Typically requires 10X magnification to clearly see inclusions. In larger carat weights, SI diamonds sometimes reveal their inclusions to the naked eye. The bigger the diamond, the more lenient the clarity grade as there is much more diamond.
  • SI3
    – This is a new “non-sanctioned” clarity grade you will hear as you begin to shop for a diamond. It is a source of conflict within the industry as GIA does not sanction this designation. What you have is an inclusion that is visible face-up to the trained eye but it really doesn’t ruin the look of the diamond face-up.
  • I1
    – Imperfect. Eye-Visible Inclusions. Often a popular choice for earrings or pendants, as these items are generally scrutinized less than diamond rings. Also a popular choice for those shopping on a budget.