Corrupted Grafstone is an interesting mana rock. It can make many different colors, but only costs 2 instead of the usual 3! To make up for that, it comes in tapped the turn you play it, and it requires a little work to get going. It has a normal mana ability (because it isn’t a loyalty ability and doesn’t target, and could add mana to a mana pool as it resolves!), so it doesn’t use the stack, resolves instantly, and can’t be responded to. But, it requires you to choose a color present among cards in your graveyard, and then you get that color. So if you only have blue cards in your graveyard, it can only make blue mana. Technically this is a choice made on resolution rather than on activation, but that doesn’t matter much with it being a mana ability! Grafstone flat doesn’t work if your graveyard is empty, and it also doesn’t work if there’s no colors among the cards in your graveyard; it can’t tap for colorless, because colorless is not a color. It also is only looking at the mana cost (and with some older cards, the color indicator; we still have those on the backs of DFCs, but the back face of DFCs don’t exist in the graveyard). To borrow from yesterday, the Emerge creatures all have colored mana symbols in their text, but are themselves colorless; if all you had in your graveyard was a Decimator of the Provinces your Grafstone could not make green mana. Lands are also colorless (mostly- Dryad Arbor is green because it has that nifty color indicator[/card]), so your Mountains aren’t gonna get your Grafstone’s red-generation online!
Today’s Rules Tip was written by Trevor Nunez