Fellwar Stone
Artifact
"What do you have that I cannot obtain?" —Mairsil, the Pretender
Legal in
Modern, Legacy, Vintage, Commander, Pauper
Rulings (7)
This works even if the opponent's lands are tapped. It only checks what kinds of mana can be produced, not if the abilities that produce them are usable right now.
2004-10-04
The ability can be activated if the opponent has no lands that produce mana, but the effect will not be able to generate any mana.
2004-10-04
It only produces one mana even if the land can produce more than one.
2004-10-04
When determining what colors of mana your opponents' lands could produce, take into account any applicable replacement effects that would apply to those lands' mana abilities (such as Contamination's effect, for example). If there is more than one, consider them in any possible order.
2009-10-01