The oval cut diamond is considered a Fancy Cut and is second only to the round diamond in brilliance. The shape was first cut in the 1960's and an oval cut diamond is a good choice if you like a sparkling diamond with a more unique shape. The oval cut has a tendency to visually elongate the finger and thus make the hand look longer and slimmer. The elongated shape can also have the effect of making the stone appear larger. The more contemporary oval cuts will have a length to width ratio (L divided by W) of 1.3 to 1.5.
All oval cut diamonds will have a bow-tie effect, or a dark area that runs right to left across the center of the diamond in the approximate shape of a man's bow tie. Due to the misalignment of the facets, the light entering the diamond is not being reflected back but out through the pavilion creating a dark area. The bow-tie is not considered a flaw, and can be minimized by purchasing a stone with a depth between 62.1 and 66% and a table between 52 and 63%. The deeper stone reduces the light lost through the pavilion, and is over all a better cut.
The good news is stone cutters are working on a new faceting technique called the Watermeyer Split-Facet that will entirely eliminate the bow-tie effect. We'll let you know when they become available on the market.
Love round stones? Read about how to select a round diamond online here.