Cut

Many people confuse cut with the shape of a diamond. Diamonds are cut into a number of shapes, depending on the nature of the rough stone. The most popular are round, marquise, oval, pear, heart and emerald, and the choice is largely a matter of personal preference. Whatever the shape, however, a well-cut diamond is the work of a master diamond cutter. When cut to good proportions, the diamond is better able to handle light, creating more scintillation, more sparkle. And that’s a great reflection on you.

BELOW: How a diamond handles light:

When a diamond is cut to good proportions, light is reflected from one facet to another and then dispersed through the top of the stone.