Tungsten carbide is one of the hardest metals. It features a mirror finish that remains shiny for years. Only a diamond is capable of scratching a tungsten ring is diamond, making it highly durable. Tungsten is significantly harder than 18K gold, tool steel, and titanium. Our rings are made from authentic tungsten carbide and are designed for comfort. 4mm Turquoise & Black Tungsten Ring Features: Shiny finish Width: 4mm Turquoise inlay Black plating Comfort fit Jewelry grade tungsten carbide Sizes: 5-10.25, including half sizes Hypoallergenic, no cobalt Free ring box included