This thick individual monotone round stacking ring is available in sizes 4.5 – 11.5, including half sizes. Material: 14k gold-fill (14k gold over brass core/no nickel), sterling silver (.925), or oxidized sterling silver. All materials are hypoallergenic. The black (oxidized) components of our jewelry will wear over time and eventually achieve a beautiful antique-like finish. This ring is designed in San Francisco and handmade in our Upstate New York production studio.