Tungsten Carbide Men's Engagement Wedding Band Ring With Shakudo Mokume Gane Genuine Tungsten, Scratch Resistant, Comfort Fit, Hypoallergenic, Cobalt Free, will NOT Turn your Finger Green Tungsten is about 10 times harder than 18K Gold, 5 times harder than tool steel, and 4 times harder than titanium. Tungsten measures between 8 and 9 on the Mohs hardness scale. Tungsten have been referred to as the "Permanently Polished Rings". "Scratch Resistant Rings" PLUS One Year Warranty Size Exchanges Included You are responsible for Shipping Charges.