The Magical Emeralds are green, octagon-shaped gems.
Features and abilities
Sonic Adventures: Dans Les Griffes De Robotnik
At some point, Sonic the Hedgehog collected a number of Magical Emeralds. However, when he was caught by Dr. Robotnik's Badniks in the Marble Temple, the robots took the Emeralds from him and gave them to Robotnik onboard his battleship. At first, the doctor was overjoyed over having the Magical Emeralds. However, he lost them when Sonic freed himself from the Badniks and threw the Emeralds off the ship with a punch.