While some 75 percent of all diamond purchased conform to the classic, 57-facet, brilliant round cut, there are a wide variety of diamond shapes or cuts, with the non-round varieties referred to as fancy shapes. Typically, a diamond polisher’s decision to produce a fancy shaped diamond stems from a the desire to retain a higher proportion of the mass of irregularly shaped rough diamonds. But there are other advantages.
 
A fancy cut diamond with a limited depth may have a wider diameter than a round stone, providing the impression of a larger stone when set in jewellery. There are five basic fancy shapes: marquise or navette, emerald-cut, pear-shape, oval and heart-shape.
 
The heart, oval, pear and marquise models are derived from the model or pattern used to cut round diamonds. The emerald cut is a step cut. Based upon the basic fancy shapes are a variety of offshoots, including princesses, triangles, cushion cuts, squares, baguettes.
 
The development of laser bruting techniques enabled the introduction of more unconventional shapes like stars and half-moons. There then are the proprietary cuts, which are diamond cuts designed in-house or commissioned by specific diamond or jewellery companies. Many of the proprietary cuts are patented and their names are trademarked.