Ruby Birthstone Emerald Cut Diamond Ring 10K White Gold10k white gold diamond and emerald cut ruby birthstone ring. The perfect July birthstone ring or mothers ring, this 10 karat white gold band has emerald cut rubies 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.