Shapes other than the standard round brilliant are called fancy shapes or fancy cuts. Their names are based on their shapes. The standard unit of weight used for gemstones. Usually abbreviated ct. G raining Graining and grain lines reflect irregularities in the crystal structure.
Proportion refers to the angles and relative measurements of a polished diamond.
More than any other feature, proportions determine a diamond's optical properties. Studies have shown that table size, crown angle, and pavilion depth have a dramatic effect on a diamond's appearance. The average size of the table facet divided by the average diameter of the diamond for round shapes, or the width of the diamond for other shapes. The certificate indicates the thickness of the girdle relative to the size of the diamond, and the condition either polished or faceted. The point at the bottom of the diamond.