The Red Gem is an optional upgrade for Sonic the Hedgehog in Sonic the Hedgehog (2006) and is one of the seven customized Gems that can be obtained in the game. It allows Sonic to perform Slow, which slows down time. When in use, the Red Gem changes the appearance of Sonic's Custom Shoes into a red pair of new shoes.
- This gem is one of the most useful gems as it slows down the time counter, which allows the player to complete the stage in "less" time. This is an easy way to get S-ranks. It is recommended that you buy the Red Gem first as getting those S-ranks gets you more money to buy the other Gems.