* Chaos Emeralds are powerful gemstones that allow Sonic to transform into Super Sonic when all seven are collected. You can find them scattered throughout the game's levels.
* Red Star Rings are a collectible that you earn by completing the game's Special Stages, which are accessed by finding special hidden rings in each level. Collecting a certain number of Red Star Rings will unlock bonus content like extra characters and gameplay modes.
So, there are no "special rings" as you might be thinking. It sounds like you might be remembering something from a different Sonic game!