Cheapest priced copy (Ice Age): $3.49 at Card Kingdom, near mint, their price list as of .
Naked Singularity 
Artifact · Rare · Ice Age · #330
Cumulative upkeep {3} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
If tapped for mana, Plains produce {R}, Islands produce {G}, Swamps produce {W}, Mountains produce {U}, and Forests produce {B} instead of any other type.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $3.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ice Age | 330 | Rare | $3.49 | — |
3 rulings from Wizards of the Coast
- 4 October 2004The ability generates a replacement effect.
- 4 October 2004If a player uses a text-changing effect to make a land type be listed as producing two different colors, the player tapping the land for mana can choose to produce mana of either color. But if it produces more than one mana, all mana is of the same color.
- 15 April 2013If a land has more than one basic land type, the player tapping the land for mana can choose to produce mana of either color. But if it produces more than one mana, all mana is of the same color.