Time Stones are gems unique to the Miracle Planet that give the holder the ability to travel through time. Like the Chaos Emeralds (once were), there are 6 of them, all of different colours. However, when Sonic the Hedgehog first travelled to the planet, he found himself heading to the planet's past with the help of a single, egg-shaped Time Stone. This particular stone was originally responsible for transforming the whole planet into a metal sphere and the creation of the first Metallix, although it is not explained how exactly the Time Stone managed this.
- In the Sonic the Hedgehog CD video game, there are actually 7 Time Stones, although they are not the devices that enable Sonic to head into the past or future. This responsibility is given to marked signposts.