Tempium or Olzaan, commonly known as Chronostone, is a blue metal that has the special ability to contain and conduct temporal energy. It is invaluable in chronomancy, and its existence within the Chronostone Crags of Zaubarovia is one of the reasons for the creation of the College of Zaubarovia.

Divinely linked to the goddess of time, Tempos, it was discovered by the Omniborn in the first era and named Olzaan. The mythical Time Gears were made from Tempium.