Diamond Weight VS. MM

What is Diamond Weight?

Diamond weight is a crucial factor when it comes to evaluating the value and quality of a diamond. It refers to the measurement of how much a diamond weighs and is typically expressed in carats. However, determining the weight of a diamond solely by carat can sometimes be misleading. To truly understand a diamond's weight, it is important to consider its dimensions, specifically its diameter in millimeters (mm).

Why is mm Important?

Measuring a diamond's diameter in millimeters allows you to gain a more accurate understanding of its weight. This is because the weight of a diamond is directly influenced by its size. By knowing the mm measurement, you can estimate the carat weight range of a diamond, which is essential for making informed decisions when buying or selling diamonds.

How to Determine Diamond Weight by mm

To determine the weight of a diamond using its mm measurement, you can follow these steps:

Step 1: Measure the Diameter

Using a millimeter gauge or caliper, carefully measure the diameter of the diamond. Ensure that the measurement is taken from the widest points of the stone.

Step 2: Use a Conversion Chart

Once you have the mm measurement, refer to a diamond weight conversion chart. These charts provide a range of carat weights corresponding to specific mm measurements. Locate the mm measurement on the chart and note the corresponding carat weight range.

Step 3: Consider Other Factors

While the mm measurement provides a good estimate of a diamond's weight, it is important to consider other factors that can affect the weight, such as the diamond's depth and cut. A well-cut diamond may appear larger than its carat weight suggests, while a poorly cut diamond may appear smaller.


Understanding how to determine diamond weight by mm is a valuable skill for anyone involved in the diamond industry. By considering the mm measurement along with other factors, you can make more informed decisions when buying or selling diamonds. So, the next time you come across a diamond, remember to measure its diameter in millimeters to unlock valuable insights about its weight.

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