The Master Emerald
Master Emerald
The Master Emerald is known as the Chaos Emeralds "controller".
Series Sonic the Hedgehog
First Appearance Sonic & Knuckles
Purpose Keeping Angel Island afloat, Neutralizing or empowering the Chaos Emeralds, Supressing Chaos
User(s) Angel Island
Knuckles the Echidna
Description Large, green, diamond-cut Emerald that resides in Angel Island

The Master Emerald (マスターエメラルド, Masutā Emerarud) is a massive, mysterious gem, held on Angel Island and guarded by Knuckles.The Master Emerald possesses the ability to control the Chaos Emerald's power,meaning it can stop the energy of the Emeralds, or enhance them.