Heart of Mar
The Heart of Mar is an important Precursor Artifact in Jak II.
The Heart is a large ruby gem, carved into the shape of a heart and crafted in Precursor metal. The ruby lights up when activated.
It is one of the items needed to activate the Rift Rider and serves as the start button for the vehicle and the Rift Gate. But once the Rift Rider was lost, when Jak, Daxter, Samos and Keira traveled through time, so was the Heart.
Mar originally made the Heart and hid it inside his Statue. It was stolen by Krew, but he lost it due to a flood while smuggling it through the Sewers. Later, Jak had to retrieve it for Krew. The statue was destroyed by Krew's men, Jinx, Mog, and Grim who blew it up and took the Heart.