This is why well-cut crowns are some important: the first image is of a new aquamarine asscher on the dop & half finished, the second is of the same stone, but with the crown I favor for asscher designs. Yeah, precision cutting really does matter, top to bottom. Finished stone in the third image: 3.42ct, 9mm asscher in Brazilian aquamarine. (Aqu1459) (Yellow reflection in the stone is from the lighting/room environment)

Asscher on dop before crown
Asscher on dop with crown
Finished aquamarine asscher