Master Emerald

In the Sonic the Hedgehog video games,the Master Emerald is the largest of the emeraldss. It can harness the power of the chaos emeralds. The master emerald is green and remains in a shrine on Angel Island, where it is protected by Knuckles. Knuckles's father Locke was the original gardian, but Knuckles came of age to take over that responsibility. On occasion the master emerald is stolen.