Obtaining the God Stone
The God Stone cannot be obtained by legitimate means in "Pokemon White." The only way to obtain the God Stone is through the use of an Action Replay or a similar cheat device. Once obtained, using such a device, the item's description is listed as "Unknown" and it has no apparent use in the game. Some of the game's additional items, however, give us some insight to this mysterious stone.
Dark Stone
"Pokemon White" features a new legendary Pokemon by the name of Zekrom and a special item called the "Dark Stone." The item description for the Dark Stone states, "Zekrom's body was destroyed and changed into this stone. It is said to be waiting for the emergence of a hero." When used, the item summons Zekrom to help in a battle towards the end of the game.
Light Stone
"Pokemon Black" features a new legendary Pokemon by the name of Reshiram and a special item called the "Light Stone." The item description for the Dark Stone states, "Reshiram's body was destroyed and changed into this stone. It is said to be waiting for the emergence of a hero." When used, the item summons Reshiram to help in a battle towards the end of the game.
God Stone
The only information given to the player about the God Stone comes in the form of its sprite. The God Stone's sprite resembles the sprite used for the Dark Stone and Light Stone in each game, albeit with a different color palette. This has lead a number of speculators to believe that the God Stone contains the body of some new legendary Pokemon not yet revealed.
Potential Use in Future "Pokemon" Releases
The God Stone is not the first item without any discernable use in a "Pokemon" game. The "Pokemon HeartGold" and "Pokemon SoulSilver" game's contained the lock capsule that had no use until the release of "Pokemon Black" and "Pokemon White." History tells us that, while this item may have no use in the current generation of games, it may have a use in a future "Pokemon" game. What that use is, however, is yet to be seen.