World Enchantment, 1GG (3)
Rare
At the beginning of each player's upkeep, that player chooses a color. Until end of turn, lands tapped for mana produce mana of the chosen color instead of any other color.
Illus. David A. Cherry

10/4/2004: Although the color may be altered, any restrictions on the use of the mana are not removed.
10/4/2004: Will not affect lands that do not produce mana.
10/1/2008: This has the supertype world. This supertype is similar to legendary. The difference is that when a world permanent enters the battlefield, any world permanents that were already on the battlefield are put into their owners' graveyards. This is a state-based action called the "world rule." The new world permanent stays on the battlefield. If two world permanents enter the battlefield at the same time, they're both put into their owners' graveyards.
Official Reprint Policy (This card is on the reserved list)
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander