Chaos Emeralds (Adventures of Sonic the Hedgehog)

The Chaos Emeralds are a set of four legendary emeralds of great power from the Adventures of Sonic the Hedgehog TV series; the Chaos Emerald of Invisibility, the Chaos Emerald of Invincibility, the Chaos Emerald of Immortality, and the The Power of Life. They appeared in the four-part saga, Quest for the Chaos Emeralds.

Invisibility
This Chaos Emerald allows the holder to become invisible.

Invincibility
This Chaos Emerald makes the holder invincible to any attack.

Immortality
This Chaos Emerald grants the holder immortality, meaning that as long as he or she has it, they can live for eternity and cannot be wounded.

The Power of Life
This grants the holder the ability to give and take people's lives away.

Other Chaos Emeralds
In Episode "Fast and Easy", there was one more Chaos Emerald fixed in a ring, the most powerful one on Mobius. It had the ability to sink any part of the planet into the sea, when placed on the altar in the Secret Zone of Mobius.

Also, Mummified Hedgehog had an emerald that made him live forever and gave Sonic a blue energy shield that protected him from Robotnik's immortality. It looked very similar to Chaos Emerald of Immortality (only it was blue instead of green), so it's possible that this was also a Chaos Emerald.