Only a few goods can be transfered via Mana Pipe; Mana Crystal Air Crystal Earth Crystal Fire Crystal and Water Crystal. Omnistones cannot. Mana Pipes can be connected to a storage building contaning any of the above, then dragged to their destination and connected again. These pipes are practical to use to extract depleted crystals from buildings to recharging buildings, and then back again. They are also useful in providing Temples or the Mage Tower with a supply of crystals to use without the need to worry about recharging (they both consume the crystal upon use). However it can be more logical to simply hand deliver crystals to some locations, such as shrines, as they don't need any more then their initial start up amount.