The Crystal of Knowledge was a blue, five-sided Kryptonian crystal that contained all the knowledge of the 28 galaxies gathered by Kryptonians.

20 years before the destruction of Krypton, the stone of Knowledge was created by Jor-El, alongside the Orb, under orders from the Ruling Council. Its purpose was to supply the Kryptonian clones on Earth, with all Kryptonian knowledge. It was divided into three Stones of Power: The Crystal of Fire, the Crystal of Water, and the Crystal of Air. The stones were sent by portal to Earth's past, and were hidden in Egypt, Central America, and East China.

The legend on Earth was that, when united, the stones would point the way to a treasury of knowledge that put the Library of Alexandria to shame. Over the centuries, many humans searched for the stones, including Countess Margaret Isobel Thoreaux, however it was foretold that if humans united them before the destined Kryptonian, they would not be able to withstand the temptation and drive the world to famine, war, and Earth's ultimate destruction.

The three stones were found and combined by Kal-El of Krypton and reformed the Crystal of Knowledge. Called Clark while on Earth, Kal-El used the crystal to form the Fortress of Solitude in the arctic. Three years later, Lex Luthor placed the Orb into the center console of the Fortress, causing it to collapse back into the Crystal of Knowledge. Four weeks after the collapse, the crystal was found near the excavation site by a LuthorCorp team looking for Lex. It was eventually returned to Clark, who used it to re-form the Fortress.