An emerald is a type of precious gemstone, usually colored green. Examples of Emeralds in the Sonic the Hedgehog series include:
- Chaos Emerald, a special gem with mystical properties and abilities.
- Chaos Emerald (Sonic the Comic), the version of the Chaos Emerald from Sonic the Comic.
- Chaos Emerald (Archie), the version of the Chaos Emerald in the Sonic the Hedgehog comics.
- Chaos Emerald (Adventures of Sonic the Hedgehog), the version of the Chaos Emerald from Adventures of Sonic the Hedgehog.
- Master Emerald, a large Chaos Emerald usually guarded by Knuckles the Echidna and his kind.
- Super Emerald, powered-up Chaos Emeralds from the game Sonic the Hedgehog 3 & Knuckles.
- Sol Emerald, emeralds which are usually protected by Blaze the Cat.
- Grey Emerald, a powerful Chaos Emerald from the Sonic the Comic continuity.
- Black Emerald
The following locations include the word "Emerald" in their names:
- Emerald Hill Zone, the first stage of Sonic the Hedgehog 2
- Emerald Coast, the first stage of Sonic Adventure, and also the first board in Sonic Shuffle
- Emerald Coast (Sonic X), a beach in the Sonic X continuity
- Emerald Ocean, a race track in Sonic Drift 2
- Emerald Town, the main setting of Sonic Battle
- Emerald Beach, a beach at Emerald Town and an arena in Sonic Battle
- Emerald Chamber, the resting place of the Chaos Emeralds in Sonic the Comic
- Emerald Valley Bridge, a bridge in Sonic the Comic
- Emerald River, a river in Sonic the Comic
- Radiant Emerald, the final track of Sonic R.
- Altar of the Emeralds, a place where the Master Emerald is kept and guarded.
- Altar Emerald, the final Zone of Sonic Advance 3.