A shallow cut oval will produce a dark area in the centre known as the bow tie effect. Keep in mind this is a characteristic of oval shapes and most fancy cuts. It is also one of the less common fancy shapes, yet very unique and economically priced. The marquise is the name given to the diamond shape that is long and pointed at both ends. Looks something like a football when viewed from the top.
Some people prefer a long and narrow cut while others prefer a shape that's short and fat.
A characteristic of this fancy shape is the dark centre known as the bow tie effect. Depending on It's depth, the real shallow ones will show a more pronounced bow tie, a deep one will show less. The heart shape is perhaps the most romantic of what are known as the fancy shapes. Look for a good cut and color and definetly not deep if you want something different this is the one. A popular cut looks like a tear drop.