The right setting can enhance the look of a diamond.

Prong
Metal claws raise a stone to allow in the most light; four or six prongs are common.
Top ring by Tiffany & Co.; bottom ring by Asprey

Cluster
Several small diamonds flank a larger center one. Ring by Kwait.

Bezel
A metal rim completely surrounds the stone.
Ring by Cartier

(Pictured below, clockwise from bottom left)
Gypsy
Stones are sunk into holes so they are flush with the ring's surface. Ring by Lieberfarb

Bar
Metal bars separate each stone. Ring by Harry Winston

Shared Prong
Adjacent diamonds share prongs. Ring by Ritani

Channel
Stones are side-by-side between metal bars. Ring by Precision Set