difference between oval and cushion cut

[blite]

Hi, What is the difference between an oval cut and cushion cut diamond (especially if the cushion cut is cut oval-ish rather than squared?)

 

[Hest88]

There are probably cut differences, but I haven't investigated them yet. The way I tell them apart is that an oval is, well, oval-shaped, while a cushion is like a rectangle with rounded corners.