Discover The Mystique: Choosing The Black Onyx Ring Which Is Perfect for You Black onyx is one of the semi-precious gemstones that is highly valued for its deep black color, luxurious finish, and magical healing properties. The smooth appearance of black onyx and its durability makes it a great choice for everyday wear in the form of rings and other types of jewelry, like black onyx earrings, black onyx bracelets, and black onyx pendants.