Ruthenium is a chemical element with the element symbol Ru and atomic number 44. It is an extremely hard platinum metal that is used in very small amounts. It is very rare; the chemist Karl Ernst Claus discovered it in Siberian platinum ore in 1844. Ruthenium production is complex and takes a lot of effort; around the world, only 20 tons of the metal are produced per year. Ruthenium is used to coat blades, giving them a unique silky sheen in a beautiful charcoal gray color.