Last week, we talked about internal characteristics, or inclusions, and identified some of the most commonly seen ones. Today, we take a closer look at external characteristics, or blemishes, which are confined to the surface of a diamond.

Because diamonds form under tremendous heat and pressure, nearly every one possesses internal and external features called clarity characteristics. These characteristics help gemologists separate natural diamonds from synthetics and simulants, as well as identify individual gems.

No diamonds are entirely without inclusions or blemishes, and these characteristics help gemologists accurately determine natural diamond clarity.

The prospect of purchasing a diamond may seem daunting, but through GIA, an unbiased authority on diamonds, you have several handy resources to help you select the highest quality diamond. First up, an overview of the 4Cs: Color, Clarity, Cut, and Carat Weight.