The Power Rock (also known as the Power Stone) is an object that appears in the Sonic the Hedgehog television series.
Appearing as roughly the size of a Chaos Emerald, the Power Rock is a major power source and is used to generate Power Rings from the Lake of Rings in Knothole Village. Without the Power Rock the lake would not be able to produce any more Power Rings.
The Power Rock was created by Sonic's Uncle Chuck, and produces one Power Ring every twelve hours. Sonic the Hedgehog broke off part of the Power Rock and gave it to Griff so that Lower Mobius would still have power left after its generator ran out of power.