Millions of years ago when the diamonds you buy today crystallized into formation, traces of minerals, gasses, and other elements were often entrapped inside them.

These tiny traces, called "inclusions," can appear like clouds or feathers under examination. They function almost as birthmarks, making each diamond unique. Many are not visible to the naked eye.

The number, the size, and the visibility of a diamond's inclusions contribute to its grade on the clarity scale. Not surprisingly, the fewer and smaller the inclusions, the more rare and valuable the diamond. Conversely, the larger, more visible, and more frequently occurring the inclusions, the lower the grade and the less rare the diamond.

Diamonds with inclusions visible to the naked eye are given grades in the lower clarity range (I-1 to I-3) - those with fewer and smaller inclusions have grades going up the scale to Flawless (FL) or Internally Flawless (IF).