Kuldaez crystal
Kuldaez crystals each possess certain mystic properties. They can be placed in a socket on a book to produce certain effects to protect or enhance them. Each crystal may be utilized by anyone of sufficient skill, but only Mages of the correct mana type will be able to recharge their effects once depleted.
Kuldaez crystals are recharged by Warrior Mages. The kuldaez crystal is charged with a matrix of elemental energy that is released when one who is not the owner attempts to touch a spellbook. This will result in either a fireball, lightning bolt or frost scythe being conjured at the unfortunate sap with grabby hands. The one exception to this rule is the hafaltu-veined variety, which will conjure an ethereal shield around a spellbook for a period of time once invoked, to shield it from the elements of rain and snow.
As with all things magical, the crystals are not infinite. They will deteriorate with time and use, eventually shattering. Those more skilled in the ways of Arcana will find less chance of harming their crystal, however.