Metallic Fossil PoE currency is applied to change the crafting manner. They are put into Resonators to have the influence. Metallic fossils provide more lightning mods but no physical ones. This one of fossils can increase the weights of mods with lightning tags by 10 times and with physical and bleed tags by 0. In Path of Exile you can either receive the fossil in Azurite Mine or purchasing from Niko the Mad. However, the cheapest and easiest way to get Metallic Fossil is to buy it from our store.