Understanding Diamond 4C Charts: A Guide to Evaluating Diamond Quality

diamond 4C charts

When it comes to buying a diamond, understanding the 4Cs of diamond quality is essential. The 4Cs refer to carat weight, color, clarity, and cut, and they are used to determine a diamond’s overall quality and value. To evaluate a diamond based on the 4Cs, diamond professionals use diamond 4C charts. In this article, we will discuss the basics of diamond 4C charts and how to use them to evaluate diamond quality.

Carat Weight

Carat weight refers to the weight of a diamond and is often used to describe the size of a diamond. One carat is equivalent to 0.2 grams. On a diamond 4C chart, carat weight is usually listed as a range, such as 0.5-0.69 carats, 1.0-1.49 carats, and so on. The larger the carat weight, the more valuable the diamond, all other factors being equal.


Diamonds come in a range of colors, from colorless to yellow or brown. The color scale used in diamond 4C charts ranges from D (colorless) to Z (yellow or brown). Colorless diamonds are the most valuable, with the value decreasing as the diamond’s color becomes more noticeable. The color grade of a diamond is determined by comparing it to a set of master stones under controlled lighting conditions.


The clarity of a diamond refers to the presence of internal and external flaws, known as inclusions and blemishes, respectively. The clarity scale used in diamond 4C charts ranges from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (inclusions and blemishes visible to the naked eye). Diamonds with higher clarity grades are more valuable, as they are rarer and more visually appealing.


The cut of a diamond refers to its proportions, symmetry, and polish. The cut can have a significant impact on the diamond’s overall appearance and value, as it affects the way the diamond reflects light. The cut scale used in diamond 4C charts ranges from Excellent to Poor. Diamonds with higher cut grades have better fire and brilliance, making them more valuable.

Using Diamond 4C Charts

Diamond 4C charts are used to evaluate the quality and value of a diamond based on the 4Cs. The chart displays the different ranges for each of the 4Cs, allowing diamond professionals to quickly evaluate a diamond’s quality based on its characteristics. To use a diamond 4C chart, follow these steps:

  1. Determine the carat weight of the diamond.
  2. Check the color grade on the chart, based on the diamond’s color under controlled lighting conditions.
  3. Check the clarity grade on the chart, based on the presence of inclusions and blemishes visible under 10x magnification.
  4. Check the cut grade on the chart, based on the diamond’s proportions, symmetry, and polish.
  5. Use the chart to evaluate the overall quality and value of the diamond based on its 4Cs.

It’s important to note that while diamond 4C charts provide a useful tool for evaluating diamond quality, they are not the only factor to consider when buying a diamond. Other factors, such as fluorescence, shape, and certification, can also impact a diamond’s value and quality.


Diamond 4C charts are a valuable tool for evaluating the quality and value of a diamond based on its carat weight, color, clarity, and cut. Understanding how to use diamond 4C charts can help you make an informed decision when buying a diamond.

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