Diamond Carat Weight

Key Points

  • The most well-known and misunderstood characteristic of the 4Cs is Carat Weight. It actually refers to the diamond's weight, not its size.
  • A diamond's cut impacts how large the Carat Weight will appear. Smaller carat weight diamonds will appear larger with higher cut grades.
  • To maximise your budget, consider buying a diamond that is slightly below your ideal carat weight. For example, instead of a 3.0 carat diamond consider buying a 2.9 carat weight.
1.5 Carat Diamond
Keep in mind, diamond prices increase exponentially with carat weight because the larger the carat, the more rare the diamond.
See 1.5 Carat Diamonds

Diamond Carat Size Chart

This print out illustrates how diamonds of different carat weights and shapes will appear when viewed from the top down.

Your diamond may differ from the printout in length/width ratio, table, and depth.

Download Chart

Carat Weight considers two factors:

  1. A Diamond's Top Diameter
    It is important to measure, in millimeters, the distance across the top (diameter) of the diamond as this is how it is viewed when set into a ring.
  2. A Diamond's Cut Grade
    A diamond's cut grade should also be considered. When a diamond is well cut (grades Very Good or higher), the light reflected out of the top making it appear larger.

How do these two Carat Weight factors help when purchasing a diamond?

The diamond's diameter and cut grade reveal that smaller carat weight diamonds will appear larger with higher cut grades (Very Good and Ideal). On the flip side, a larger carat weight diamond could appear smaller with lower cut grades (Good, Fair and Poor).

Expert Buying Tips

  • If a large carat weight is important to you, yet you're working within a strict budget, consider a diamond with a good cut, SI1-SI2 clarity, and an I or J colour grade.
  • Diamond prices jump at the full- and half-carat weights. Diamonds just below these weights cost significantly less, and, because carat weight is distributed across the entirety of the diamond, small size differences are almost impossible to detect.
  • Keep in mind that the smaller the finger, the larger the diamond will appear. A 1.5-carat diamond solitaire looks much larger on a size 4 finger than a size 8.
  • Not all settings will fit all diamond carats or shapes. If you have already selected a setting, check the diamond specifications of your ring or ask your Blue Nile Diamond and Jewellery Consultant (00353 1 899 1351) for help. If you need a special jewellery piece created, Blue Nile can accommodate almost any request.

Next, learn about Diamond Cut.

Have A Question?

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