Fellwar Stone checks the effects of all mana-producing abilities of lands your opponents control, but it doesn't check their costs. For example, Vivid Crag has the ability "{T}, Remove a charge counter from Vivid Crag: Add one mana of any color." If an opponent controls Vivid Crag and you control Fellwar Stone, you can tap Fellwar Stone for any color of mana. It doesn't matter whether Vivid Crag has a charge counter on it, and it doesn't matter whether it's untapped.
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.
Fellwar Stone doesn't care about any restrictions or riders your opponents' lands (such as Ancient Ziggurat or Hall of the Bandit Lord) put on the mana they produce. It just cares about colors of mana.
Last observed on Scryfall 2 months ago at $1.21. Over the trailing 90 days the price moved between $0.99 and $1.22 across 43 observations. Cross-checked across TCGplayer, eBay sold, Cardmarket EU, and Star City.
This printing is one of 2 catalogued treatments from C15 — the lineup includes Nonfoil alongside the standard finish. Across our catalog the Rarix library tracks every variant in the same family so collectors can compare price, scarcity and demand inside a single lineage.
Card #254 of *Commander 2015*, the set that shipped alongside the November 2015 Commander 2015 release.
Card type: Artifact, printed at uncommon. Uncommons fill the middle-tier slots in a standard booster configuration. Mana cost: {2} (2 converted).
Legal in Modern, Legacy, Vintage, Commander, and Pauper.
EDHrec ranks this card #18 in Commander, putting it in the format-staple tier of the format's playable pool.
Illustrated by John Avon. Rarix catalogs 1,840 other cards credited to this artist.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. John Avon
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
The colors of mana are white, blue, black, red, and green. Fellwar Stone can't be tapped for colorless mana, even if a land an opponent controls could produce colorless mana.
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.
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.
It only produces one mana even if the land can produce more than one.
