Usually the diamond rough will be cut into whichever shape that requires the least amount of sacrifice. Marquise and oval shapes should have a length thats exactly twice the size of the width. If they are too narrow or too wide, the stone will loose light and appear too dark.
The first thing to decide when purchasing Tiffany Style Diamonds is the shape of the stone. There are nine major shapes of diamonds.
We shall probably never know when the first Tiffany Style Diamonds was discovered, but we do know that, from ancient times until the eighteenth century, all the worlds diamond engagement ring came from India.