Red Gem

The Red Gem is 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.

Location
In Sonic the Hedgehog (2006) the Red Gem becomes available at the local shop, once the player clears Tails' version of the Wave Ocean in the main story. It can then be bought for 7000 Rings.