Metal runes are created by bringing 5 pure essence (each) and 2 bars of any metal (each) to the Metal Altar. The resulting rune differs depending on the type of metal brought. For instance, if you were to bring 10 Pure Essence and 4 Adamant bars, you would get 2 Metal Rune (Adamant)s. The Metal Rune is used in the spell Metalize.