They are Larger than Most People Expect
Diamond size is usually associated with how big the top of the diamond looks. In an oval diamond, the top surface looks larger than that in a round diamond, owing to the fact that the former has a larger surface area, by as much as 10%.
They Make the Fingers Look Longer
Being elongated, oval diamonds create the illusion of longer fingers. Most people like this effect.
Length to Width Ratio is Crucial
They are Very Sparkly