The Chaos Emeralds are objects in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. They were the alternate versions of the Chaos Emeralds from another reality. They are seven magical gem stones possessing unlimited power, including the ability to grant super forms.
Sonic Chronicles: The Dark Brotherhood
Knuckles the Echidna once used the green Chaos Emerald to lure a mysterious emerald thief into a trap created by Miles "Tails" Prower. When the thief, or rather thieves showed themselves, they where able to subvert the trap and defeat Knuckles before disappearing, taking Knuckles and the Emerald with them.
Some time later, Sonic the Hedgehog harnessed the seven Emeralds' power, becoming Super Sonic, aboard Eggman's Space Armada. Tricking Sonic into believe he had given up, Dr. Eggman sprung a trap on the transformed hedgehog that drained the Emeralds' power from his body. Eggman used this power to fire an energy beam at the earth, splitting it apart and releasing "it". After Sonic had transformed into the Werehog, Eggman deposited him and the drained Emeralds out of an air-hatch, leaving them to fall to the earth.