The Purple Gem is a purple emerald cut gem, similar in appearance to a Sol Emerald, that can be equipped on Sonic's Custom Shoes. When used, it allows Sonic to perform Scale, which shrinks him down in size and allows him to jump in mid-air without limit.
While having set Sonic's Custom Shoes to utilize the Purple Gem's ability, the Purple Gem changes their appearance into a purple pair of shoes resembling Sonic's 2G Hi-Speed Shoes.
- The Purple Gem is the most expensive Gem in Sonic the Hedgehog (2006).
- The Purple Gem can be used to skip certain playable characters' sections in Acts, such as Tails in Wave Ocean, and Silver in Kingdom Valley.
- It is possible to "zoom out" the camera by activating and deactivating the Purple Gem. The camera will get stuck in its current position until the player stops activating and deactivating it.
- Official In-Game Description.