The cut of a diamond determines how it reflects light, which is responsible for its sparkle or brilliance. A well-cut diamond is cut by a skilled professional to the best proportions possible so that light will be reflected from each of its mirror like facets and disperse through its top.

Too shallow a cut will let light escape through

a diamond’s bottom, causing it to appear dull.

Too deep a cut will allow light to be lost through a diamond’s sides, making it appear dark. Because a diamond with perfect colour and clarity could nevertheless have poor brilliance if it is not well cut, many gemologists consider this to be the most important property to note when choosing a diamond. Diamonds can carry cut grades of Excellent, Ideal, Very Good, Good, or Fair.

Shape Diamonds do not show all of their beauty as rough stones; instead, they must be cut and polished to exhibit the characteristic fire and brilliance that diamond gemstones are known for. Diamonds which are not cut to the specifications of round brilliant shape are known as fancy cuts.