Purple Gem

The Purple 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 Scale, which shrinks Sonic down and allows him to jump without limit. When in use, the Purple Gem changes the appearance and colors of Sonic's Power Sneakers into a purple pair of new shoes.

Location
In Sonic the Hedgehog (2006) the Purple Gem becomes available at the local shop, once the player clears Sonic's version of Kingdom Valley in the main story. It can then be bought for 14,000 Rings.