Also known as: マスターエメラルド
The large, green gemstone watched over by Knuckles The Echidna. Its power keeps his homeplace, Angel Island, afloat in the sky.
The God of Destruction, Chaos, was sealed inside it along with Tikal following the destruction of the Knuckles Clan. The emerald has the power of cancelling the effect of the seven smaller Chaos Emeralds. If it shatters, Knuckles is capable of sensing its pieces and placing them back together.