Black and gold make a beautiful and elegant combination. A black onyx ring is a perfect accessory for any outfit. A long time favorite of jewelry designers, aquamarine is the birthstone of March. The diamond-like brilliance of an aquamarine ring is sure to attract attention. Sapphire is the birthstone of September, and one of the most popular gemstones on the jewelry scene today. The deep blue color of a sapphire ring is just right for an evening out.