Diamonds are formed under incredible amount of heat and pressure within the earth. They often contain unique birthmarks, either internal (inclusions) or external (blemishes). Inclusions can interfere with the passage of light through the diamond and the fewer the inclusions, the more brilliant a diamond. Blemishes include surface irregularities and also lower the value and luster of a diamond.
A diamond’s clarity rating is based on the inclusions and blemishes that are visible under the 10x magnification. Diamonds without these characteristics are rare and rarity affects a diamond’s value.
Diamond grades range from Flawless to Included 3. Flawless diamonds are those which are completely free of blemishes and inclusions and Included 3 are those which possess large, heavy blemishes and inclusions visible to the naked eye.
The chart explains the eleven different clarity grades assigned to diamonds along with their characteristics.