The onyx amulet is made by using an Onyx stone and a Gold bar on a furnace with an Amulet mould in your inventory, or on your tool belt. It requires a Crafting level of 90 and provides 165 experience when made. The amulet must be strung before wearing by using a ball of wool or the String Jewellery spell (Lunar spells are required to cast). Stringing provides 4 Crafting experience.