Pure silver, for example 99.9% pure, is generally too soft for making objects for use. Therefore, the silver is usually alloyed with copper to give it strength while keeping the ductility and beauty of the precious metal. Other metals can replace the copper, to improve various properties of the basic sterling alloy such as increasing resistance to tarnish. These replacement metals include germanium, zinc and platinum, as well as a variety of other additives, including silicon and boron. Alloys such as argentium silver have appeared in recent decades. Argentium silver has some germanium added, and resists tarnishing well.