- One who has successfully completed recognized courses of study in gem identification, grading and pricing, as well as diamond grading and appraising; e.g., a “Gemologist” or “Graduate Gemologist” of the Gemological Institute of America or a “Certified Gemologist” of the American Gem Society.
- The outer edge, or periphery, of a fashioned stone; the portion that is usually grasped by the setting or mounting; the dividing line between the crown and pavilion.
- Girdle Facets
- The 32 triangular facets that adjoin the girdle of a round brilliant-cut stone, 16 above and 16 below. Also called upper- and lower-girdle facets, upper- and lower-break facets, top- and bottom-half facets, skew facets or cross facets. Facets are sometimes placed directly on the girdle, in which case the stone is usually said to have a “faceted girdle,” to have a polished girdle or to be “girdle faceted.”
- Girdle Reflection
- When a diamond has a pavilion that is too shallow or flat, the girdle is seen reflected in the table.
- Girdle Thickness
- The width of the outer edge, or periphery, of a fashioned diamond or other gemstone. In a rounded style of cutting, such as the round brilliant or pear shape, the girdle edges, when viewed parallel to the girdle plane, consist of undulating lines caused by the intersection of the flat facets with the curved girdle. In such stones, the girdle thickness is measured across the midpoints of opposing upper- and lower-girdle facets.
- The step in the fashioning process of a diamond in which the stone is given a circular shape. The stone is held in a lathe, or cutting machine, and another diamond, called a sharp, which is affixed to the end of a long dop that is supported by the hands and under an armpit, is brought to bear against the stone behind shaped. An older method consisted merely of rubbing two diamonds together until the desired shape was obtained.