In looking at diamonds, shape refers to the overall design of the stone.
The most popular shape is the familiar round diamond, but you’ll also see beautiful stones cut in pear, heart, oval, marquise, emerald cut, princess cut, radiant cut and other shapes.
The proportion of a diamond compares its height with its width.
Cut means how well the design of the diamond, its shape and proportion, has been crafted by the diamond cutter.
Cut is a major determinant of a stone’s value. The purpose of a good cut is to give diamonds maximum brilliance.
Brilliance means the amount of sparkle or light that’s returned to your eye from the diamond. Diamonds that maximize this quality are often said to be the most valuable.