Bearding (6.18)
Bearding describes man-made inclusions that are caused by the girdling (rounding) of elliptically- shaped diamonds. Girdling will be covered in more detail in the diamond cutting section of this course, but for now we will briefly go into the cause and effect of bearding. The cutter rounds a stone by first mounting it on a lathe-like girdling machine which spins rapidly. An industrial diamond is mounted in the end of a girdling stick which is pressed against the rotating diamond that is being shaped. Especially in the lower grades, diamond-cutting is often rushed by the excess force that the girdler puts on the stone being shaped, which causes the bearding. When such a stone is viewed at its surface under 10x, hundreds of tiny chips will be seen, most obviously between the girdle and the polished upper and lower girdle facets. Then looking just below the surface, behind these tiny chips, feather-like inclusions will be seen traveling into the diamond that gives it the appearance of a scraggly beard. Even when actual bearding doesn’t occur, the girdle may appear rough instead of the waxy, smooth surface that it should have. Some cutters will attempt to cover the bearding by faceting the girdle, but this may or may not work. A faceted girdle may actually make the pitting easier to see, with the small open feathers on the surfaces and the scraggly beard behind the facets. In higher clarity stones, this could definitely affect the final grade, but in SI to imperfect grades, it is much less likely to do so.
