Resurrection stone

The Resurrection Stone was one of the Deathly Hallows.Created by,or given by Death to,the second Peverell brother,it had the power to bring people back from the dead but not to make it as if they had never died.

As told in Harry Potter and the Deathly Hallows,it was in fact set into Gaunt's Ring and passed from the Peverell family into the Gaunt family before being made into a Horcrux after Tom Riddle stole it from his uncle Morfin Gaunt.It ceased to be a Horcrux after Albus Dumbledore attacked it with the Sword of Gryffindor.