Gems are the magical currency of Dominions, representing distilled magic power of a magical path. They are consumed by forging items, casting rituals, empowering mages to increase their magical paths, and casting certain combat spells. They are obtained mostly through magic sites, making site searching a critical activity for building up a gem economy. Other ways to obtain them include certain artifacts, some global enchantments, and to a lesser extent certain random events. Blood magic uses blood slaves instead of gems which have a number of mechanical differences discussed below.
As with magic items, gems can be freely allocated to any commander in a province with a lab, and may be returned to the stockpile in much the same way. In provinces without a lab, they can be passed freely between commanders. Because gems held by a commander that dies cannot be recovered, having another stealthy commander hold reserve gems to replenish those used in combat magic can be helpful in mitigating damage from mage deaths.
Gems may be converted from one type to another at rather great expense through alchemy. A very limited number of commanders may perform a much more efficient transformation with the carcass collector and pearl cultivator abilities.
Similarly to gold and magic items, gems may be traded between players. It is hard to assign a gold value to gems, as only earth and fire may be directly converted into gold through spells such as and . The gold return from such spells is based both on the magic path of the caster, as well as the alchemist ability.
Blood slaves are in many ways the gems for blood magic, but they have a number of key differences: