Carats of Gemstones, Moissanites and Lab Diamonds

The size of a stone or diamond is often measured in millimeters (mm) for its dimensions and carats (ct) for its weight. However, the relationship between size in millimeters and carat weight is not always a straightforward conversion, as it can vary depending on the specific gemstone’s density and cut. Generally, as a gemstone’s size (in mm) increases, its carat weight also tends to increase.

For round brilliant-cut diamonds, there’s a general guideline that you can use as a reference:

• 1 mm diameter diamond is approximately 0.005 carats
• 2 mm diameter diamond is approximately 0.03 carats
• 3 mm diameter diamond is approximately 0.10 carats
• 4 mm diameter diamond is approximately 0.25 carats
• 5 mm diameter diamond is approximately 0.50 carats
• 6 mm diameter diamond is approximately 0.75 carats
• 7 mm diameter diamond is approximately 1.25 carats
• 8 mm diameter diamond is approximately 2.00 carats

It’s important to note that this conversion is a general guideline and may not be accurate for all gemstones or diamond cuts. The density of the specific material and the cut style can affect the weight-to-size ratio