This is a lovely, circa 1840, rose diamond cluster. It has a silver shank, and the foiled diamonds are also set in silver, but part of the split shank is in 15 ct yellow gold, and is part of the setting for the cluster. The ring has a diamond surround of 8 rose cut diamonds, and then there is a larger diamond in the center. No, I don't know the weight of the diamonds. First of all, one does not weigh rose cut diamonds the same way that modern diamonds are weighted, and 2nd, I would have to remove the diamonds from their setting to weigh them. The ring is a size 5 and 1/2, though it could be sized by someone who is used to working with antiques jewelry. The diamond cluster measures 5/8 of an inch around if that helps you with the size. This is a nice ring, and one in very good condition.
Rose Cut Diamond Ring Cluster, Early Victorian