Metals commonly used in restorations can be broken into 3 classes; High Noble, Noble, and Base. This is true for metal copings, PFMs, and full metal crowns. These categories are comprised of a mix of gold, platinum, palladium, silver, copper, indium, iridium, zinc, rhenium, cobalt, chromium, beryllium, molybdenum, tungsten, silicon, manganese, iron, carbon, tin, gallium, ruthenium, niobium, and tantalum