To get from the raw diamond to the cut gemstone it requires a skilled hand of a master cutter.
Proportions are everything.
The better the proportions, the better the diamond handles light to create more sparkle. There are a number of shapes which diamonds traditionally take, depending on the original nature of the rough, uncut stone. It all comes down to what you like. The make of Diamond is often referred to as its cut, or as its proportion and common diamond shapes are brilliant round, heart, oval, marquise, pear, princess, and emerald. Of course some Diamond retailers simply say they have only fine makes and leave it at that.