Cut – 4C’s of Diamond Certification
Evaluating the Cut of a Diamond
Cut does not refer to shape (pear, oval), but the symmetry, proportioning and polish of a diamond. The cut of a diamond greatly impacts the brilliance of a diamond. So even if all the other 4C’s are graded perfect, if the cut is bad, it will gleam less. For this reason, many gemologists consider cut quality to be the most important diamond characteristic.
Proportions of a Cut Diamond
Diameter: Diamond width as measured through the girdle.
Table: The largest facet of a gemstone (flat top).
Crown: The section of a diamond above the girdle plane.
Girdle: The narrow band around the widest part of a diamond.
Pavilion: The bottom portion of a diamond, extending from the girdle to the point of the stone.
Culet: The surface at the tip of a gemstone. The preferred culet is not visible with the unaided eye.
Depth: The height of a gemstone measured from the culet to the table.
There is no universal standard as to what the perfect proportions are for a cut diamond. However, there is some agreement regarding how diamonds should be cut to optimize brilliance and dispersion. For example it is known that the width and depth greatly effect how light travels within the diamond, and how it exits in the form of brilliance.
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