Crystal of Kronos

The Kronos Crystal was a trident-shaped crystal which contained the most fearful and powerful Chronovore, Kronos. (DW: The Time Monster) At the moment of its birth, the Guardians of Time imprisoned it in the Crystal, which was created by the Key to Time, and then hurled into the Time Vortex, to land wherever it was carried. The crystal was hidden throughout time on many worlds until it arrived on Dæmos. The Dæmons brought it to Earth, where they gave it to the people of Atlantis, which they used to help make their civilization flourish. (PDA: The Quantum Archangel) King Dalios later forbade use of the Crystal, knowing that it would ultimately doom his people.

In the 1970s, The Master acquired a fragment of the Kronos Crystal, and used it to manifest Kronos in the hopes that he could bind Kronos to his will. The Master failed, and, returned back in time to the later days of Atlantis, Kronos destroyed the city. (DW: The Time Monster)

REF: The Universal Databank speculated that the Kronos Crystal was a Kontron crystal.