Encrusted fossils are in stackable currency class. This on of fossils allows the item to either keep the same number of sockets, or receive them up to its maximum. It does not ensure changing white sockets on the item and is not able to roll more than 3 white items. In Path of Exile game the fossil can be applied on shield, armor, boots, helmets and gloves. One can buy POE Encrusted fossils from Niko for 100K azurites or can drop it behind fractured walls in Magma Fissure.