The Soul Urn is a block created using the Filtered Hopper. Its purpose is to make Soul Forged Steel or the creation of powerful devices, such as the Block Dispenser. To make a Soul Urn, place an empty urn right under a Filtered Hopper and place a Block of Soul Sand into the filter slot of the Filtered Hopper. Once you have done that take 8 Ground Netherrack and throw it on to the Filtered Hopper. The Soul Sand will filter the tormented souls from the Netherrack, converting it to Hellfire and safely store up to 8 souls in the internal buffer of a Hopper that is receiving Mechanical Power (from any side other than top or bottom). Once the hopper containers 8 soul it will force the souls from the soul sand to move down into the urn, thus creating a Soul Urn.