|This article belongs to the Classic Timeline|
The Petropia Back-up crystal is a sacred artifact for the people of Petropia and it is well known for its nearly limitless power.
At first it was thought that it was simply an energy source. It was later discovered to be a genetic back-up of every Petrosapien, along with Petropia itself. The Guardian of Petropia used its immense power to restore Petropia and her people.
Since the beginning of time, the DNA of the Petrosapien people and their memories has been stored in the crystal's molecular lattice. It can only be used properly when a rare alignment of stars occurs, and only by a Crystalsapien or Petrosapien who is attuned to the crystal.
Prior to The Secret of Chromastone, Tetrax learned, while exploring the ruins of Petropia, what the true nature of the crystal was. He then stole it back from Vilgax and gave it to Sugilite. It was used to restore Petropia and his people by Chromastone and Ben (as Diamondhead), respectively. It was returned to its home and given to its original guardian when he was revived, where it will be protected.
- Ben 10: Secret of the Omnitrix (first appearance; flashback)
- The Secret of Chromastone (first reappearance)
- It is known to be the Petrosapiens' most sacred crystal.
- The Petropia Back-up Crystal's purpose of serving as a way to restore Petropia and the Petrosapiens is very similar to the Omnitrix's purpose of preserving DNA samples in order to bring them back from extinction.