Emerald Birthstone Emerald Cut Diamond Ring 10K White Gold10k white gold diamond and emerald cut emerald birthstone ring. The perfect May birthstone ring or mothers ring, this 10 karat white gold band has emerald cut emeralds and diamonds alternating half way around the ring. All birthstone rings and mother's rings are available in all birthstones, although the April (diamond) version may cost more. Looks great worn alone, or as a stackable ring.