Yellow cushion-cut diamond ring with white pear-shaped diamond shoulders from Graff.

Ruby-and-diamond ring set in platinum from Oscar Heyman, 800-642-1912.

Marquise-cut pink diamond in a pave setting from OGI Ltd.

Platinum setting with cushion-cut emerald and smaller white diamonds from Oscar Heyman, 800-642-1912.

Asscher-cut yellow diamond in a platinum setting from Harry Winston.

Cat's-eye-and-diamond ring from Oscar Heyman, 800-642-1912.

A radiant-cut intense-yellow diamond surrounded by six brilliant-cut diamonds in a platinum setting by McTeigue & McClelland.

Extremely rare fancy-intense pink-diamond ring in a platinum setting from Harry Winston.

Fancy yellow-diamond surrounded by smaller white diamonds in a white-gold setting from Oscar Heyman, 800-642-1912.

Asscher-cut yellow-diamond ring with fancy-shaped diamond shoulders in a platinum setting from Graff.

Oval-cut sapphire-and-diamond ring with channel band set in platinum from Oscar Heyman, 800-642-1912.

Antique pear-shaped yellow-diamond ring from Paolo Costagli.

Fancy yellow-diamond ring set in platinum from Oscar Heyman, 800-642-1912.

Ruby-and-diamond ring set in platinum from Oscar Heyman, 800-642-1912.

Alex sapphire-and-diamond ring in a platinum setting from Oscar Heyman, 800-642-1912.

Marquise-cut yellow-diamond engagement ring from Paolo Costagli.

Emerald-cut yellow diamond with fancy-shaped diamond shoulders in a platinum setting from Graff.

Emerald-and-diamond ring from Oscar Heyman, 800-642-1912.