Diamonds come in a variety of shapes. Do not confuse cut with shape. Cut is what determines how well-cut your diamond is, where as diamond shape is the shape it was cut into.
Round Brilliant - Do not confuse with Round. The Round Brilliant is the modern version of the Round which has been refined for maximum shine. The Round Brilliant is by far the most popular and has the best angles to shine maximum brilliance.
Oval - Not as popular for solitaires, but very popular for three stone anniversary rings, with two matching diamonds on the sides.
Princess - A square cut diamond that has refractive properties almost near round brilliant. The princess is the preferred square cut shape over Radiant and Asscher.
Emerald - A more traditional shape, the Emerald is not as popular as it once was, but still retains its old world elegance.
Marquise - Like the Emerald, the Marquise is a traditional shape. This is probably the fourth most popular shape behind the Round, Princess and Oval.
Pear - Mostly used in pendants, the Pear shape diamond is shaped in a tear drop shape and has fairly good proportions to refract light well.
