Prong Setting
Small metal claws gripping a stone at its edges. Maximum light, minimum protection.
Prongs hold a stone with three to eight claws, leaving the sides open so light enters from every direction.
That openness is why diamonds are set this way and why pearls usually are not: a claw grips a pearl at exactly the point where nacre is thinnest.
Prongs also snag on fabric and bend, so they need checking every year or two.
When you are buying
Run a finger over the claws. If they catch, they are lifted, and a lifted claw is how stones are lost.
Bezel Setting
A metal rim wrapped around the edge of a stone or pearl to hold it. The most protective setting there is.
Half-Drilled
A pearl drilled only partway through, so it can be cemented onto a post. How pearls are mounted in studs and rings.
Finger Ring
A ring set with a pearl, usually a single dome-backed or button pearl in a protective setting.
Kundan
A setting technique where highly refined gold foil is pressed around stones to hold them, with no prongs or claws.