It was thought to be an artifact of great power, said to grant invincibility and possibly immortality to whomever possesses it. The stone was also said to be a wish-fulfilling jewel and/or a Buddhist Holy Grail of sorts.
Marco Polo found the stone when he found Shambhala. It was housed in a great temple in the middle of the city, that also housed the Tree of Life.
Nate first learns about it after finding a map, hidden inside an ancient Mongolian oil lamp in an Istanbul museum. The map implied that the stone was in Borneo with Marco Polo's lost fleet, but after looking deeper into other diaries by Polo at Lazarevic's camp, Nate deduced that it was still in Shambhala.
Throughout the game Nate finds himself wary over the actual existence of the mythological traits of the stone, whereas Lazarevic is very convinced, having spent years on its exhibition. Motivated by Karl Schäfer & with the help of Elena Fisher and Chloe Fraser, Nate struggles to beat Lazarevic and Harry Flynn to the chase. When in Shambhala, at the sacred shrine, it was revealed that the stone itself wasn't a sapphire but amber (fossilized resin), insinuating that Schäfer as well as Marco Polo had it wrong. This amber was the solid version of the sap from the Tree of Life (also known as the blue resin Nate finds throughout the game); the resin is what actually bestowed the power to bring invincibility. It is destroyed when Nate defeats Lazarevic by exploding the roots of the Tree, ultimately destroying the entire city of Shambhala.
- 70 years ago, Nazi Germans also sought after the Cintamani Stone but were killed by Schäfer.
- Around that same time, and judging by the bodies and weapons lying about the outer areas of Shambhala, others had apparently tried to get to the stone, but were killed by the Guardians.
- Tamerlane and Genghis Khan were said to have had slivers of the stone; this granted them great power.