The hardest metal used in jewelry making, tungsten carbide rings are the most scratch resistant rings available! Tungsten by itself is extremely strong (as strong as titanium) but when carbon is added to create an alloy, it becomes 3 to 5 times harder. Tungsten carbide is extremely durable and scratch resistant, but that same hardness property creates the possibility of shattering or cracking if struck in just the right manner. Although breakage is rare, your ring will be covered under your Lifetime Manufacturer's Warranty. In creating tungsten carbide, a very small amount of nickel binder is used, so small, that most people with nickel allergies have no reaction to it. Tungsten carbide rings can be removed with vice grips in case of emergencies.