The shape of a rough diamond crystal is octahedral. The cutter must cut in such a way as to maximize its weight, brilliance, and minimize its flaws. About 75% of all diamond sold are round brilliant. There are other shapes like emerald, princess, oval, marquise, heart, pear shape.

The round brilliant gives the most brilliance . Its facet and proportion have been perfected using science and mathematical analysis conducted by Marcel Tolkowsky in 1919. Modified brilliants have the same facets and facet arrangement. The following are all modified brilliants: marquise, heart, oval and pear shape.

Step cut diamonds do not sparkle as much as the brilliant cut diamonds. However they highlight the clarity of the diamond. If there are any inclusions these will be visible. Example of a step cut diamond is the emerald shape.

The mixed cut is a combination of the brilliant and step cut. The step cut is applied on the crown while the brilliant cut is given to the pavilion. An example of this cut is the Princess cut.

Contrary to expectations, fancy cut diamonds are more affordable than the brilliant round cut diamond. This is because they are cut to maximize their weight. There is less cutting and waste for a princess cut. A rough diamond cut into a brilliant round may only yield half a carat compared to another 50% more carat for fancy cut diamonds.

You also need to consider the shape of your hands. If you have short fingers or small hands wearing a marquise or oval shape diamond ring will wear your fingers look longer.

Pear shaped diamonds tend to be used for pendant and earrings.

If you are concerned about clarity and color then go for the brilliant round as it covers these flaws well with its brilliance. On the other hand inclusions and poorer coloration is most obvious in the emerald shape since its shape is the most uncluttered of all.Therefore, it is imperative to pick a higher quality emerald shape diamond if you are interested in this shape.

If you are a romantic at heart and want a diamond to symbolize your love to your spouse , consider getting a heart shape diamond. It is actually a pear shape with a cleft at the top.

The size of a diamond is also affected by the shape of the diamond. A one carat emerald diamond with a bigger table and less depth give an appearance of bigger size diamond than a two carat brilliant round with a smaller table but greater depth.

You can find diamonds in these various shapes at http://www.alljewelry.info/diamond.html. http://www.buy-diamonds.net/cut_of_a_diamond.htm tells you how the cut of a diamond influences the value of the diamond.