From Bulbapedia, the community-driven Pokémon encyclopedia.
Damos holding the Jewel of Life
Jewel of Life (Japanese: 命の宝玉 Jewel of Life) is an artifact that was the central focus in Arceus and the Jewel of Life.
In ancient times, Arceus was rescued by Damos after suffering critical injuries by protecting the world from a meteor's impact. In gratitude, Arceus created the Jewel of Life out of its Splash, Meadow, Earth, Zap and Draco Plates and gave it to Damos to make the desolate land of Michina Town rich and fertile. Arceus stated that the Jewel of Life does not break due to the fact that it is composed of its Plates.
Damos was to return the Jewel to Arceus on the day of the solar eclipse, but due to being controlled by Marcus, he betrayed Arceus and did not return the Jewel. When Arceus woke from its long sleep and came to Earth to get its revenge, Sheena attempted to return the Jewel of Life, but it ended up being a forgery. The real Jewel of Life remained in Marcus's staff for many years until it was discovered by Jessie, James and Meowth. However, due to Ash, Dawn, Brock, and Sheena changing the past and returning the Jewel to Arceus, it soon vanished in the future.
In the manga
In the movie adaptations
The Jewel of Life appeared in Arceus and the Jewel of Life.