Keep things simple with black gemstones, such as onyx. Go for an all-white outfit adorned by black jewelry. If you want a simple, sleek look, black and white look for a timeless effect. Add a simple, delicate necklace with black onyx. For a stunning and sexy vibe, black gemstones such as onyx work correctly with white outfits, plus it set you apart from the usual black or dark-colored evening dresses.