Diamond girdle bearding is a term that is used by gemologists to denote man-made inclusions in a diamond during the girdling and polishing of rough diamonds. Usually, this type of inclusion affects the 1 and a half carat diamond ring price only when you go for higher clarity grades, but it cannot be overlooked when evaluating the worth of any diamond.
During the cutting and polishing phase, the diamond is mounted on a lathe-like machine. This machine has an industrial grade diamond at the end of the girdling stick, which is pressed onto the rough stone, spinning rapidly to shape it as per the desired design. Sometimes, this “pressing” is rushed by the diamond cutter, which in turn, exerts more pressure to the rough stone and causes the bearding.
To check if the diamond is bearded, gemologists use a 10x magnification loupe, and look for small feather-like inclusions between the girdle and the facets. These inclusions will look like moving into the heart of the diamond, typically imparting a beard-like appearance to the gemstone. Although this is inside the stone, the diamond girdle bearding makes it appear rough instead of having a smooth finish. Even faceting the girdle does not work to cover the bearding.
As said, the inclusion looks more dominant in higher clarity stones, in turn affecting the 1 and a half carat diamond ring price. However, it is much less likely in case of SI or lower clarity grade diamonds.