A Closer Look at the Four C's of Diamonds


Every diamond is different, just like the people who wear them - so how do you place a value on something as unique as a snowflake? In the mid-20th century, the four C's were created by the Gemological Institute of America (GIA) as a way of measuring the value of a diamond. I'm going to break down this blog post by each of the C's and explain some of what is done to evaluate each so that you have a better understanding of how diamonds are valued the next time you are on the hunt for some new bling.


The first of the four C's is actually a little misleading. Diamonds aren't valued by their color but by the lack of it. Most gem-quality, chemically pure diamonds have no hue at all, like perfect, pure water. Along with developing the C's themselves, the GIA also developed a color-grading system that uses letters. A colorless diamond is given a D on the color scale: D-rated diamonds have the least amount of color possible. The scale goes all the way to Z, with Z being the most color for a gem-quality diamond. To determine the rating on the scale, stones are compared to master stones of an established color in precise viewing conditions under controlled lighting.


The absence of internal characteristics and external characteristics caused by the process by which diamonds are created is clarity. The internal characteristics that result due to carbon being exposed to significant amounts of pressure and heat deep within the earth are called inclusions, while the external characteristics are blemishes. There are a bunch of things that make a difference in the clarity evaluation of a diamond, such as the nature, position, size, and relief of these characteristics and how many there are. No diamond is completely pure, but the closer to flawlessly clear it is, the more valuable it is.


Diamonds are known for how much they sparkle and the amount of light they transmit. The cut is not about the shape the diamond is cut into but about how well the stone is fashioned so that the most light possible is returned when it reflects through the diamond.

Carat Weight

The last of the four C's is the carat weight. A carat is 200 milligrams, and it can also be divided into 100 points. If a diamond is below a carat, a jeweler may describe it by its points; for example, a diamond weighing 0.25 carats may be referred to as a 25-pointer. If a diamond is above a full carat, decimals are used to describe the carat weight.

I hope this helped to clarify for you some of what goes into determining a diamond's value. I know for a long time, I misinterpreted some of the four C's, cut and color especially. How much do you know about the four C's, and how much do each of them matter to you personally? Let me know in the comments! I'd love to hear your opinions.