What are cluster rings? A cluster ring France is called a “marguerite”, the daisy flower. Then you understand that’s a name given to a broad range of ring styles with one thing in common : gemstones ‘clustered’ together. Most of the time there is a central stone in an entourage of smaller stones. They come in a wide variety of shapes: round, oval, square. Cluster rings can be set with all types of stones, but the great classic is the ring with a central sapphire surrounded by diamonds, like Kate Middleton’s ring.