The narrow band around the perimeter of a polished or faceted diamond or colored gemstone. A girdle separates the crown from the pavilion facets and will vary in thickness depending on a stone’s individual style and shape. Thickness is measured on a scale from extremely thin to extremely thick, with mid-range thickness being preferred. A girdle can be further described as bruted, faceted, polished, or a combination of these. See also Proportions.