Land Gemstone Mine enters the battlefield with three mining counters on it.
Special
{T}, Remove a mining counter from Gemstone Mine: Add one mana of any color to your mana pool. If there are no mining counters on Gemstone Mine, sacrifice it.
Illus. Brom

10/4/2004: Sacrificing this card when the last counter is removed is part of the effect of tapping it for mana.
9/25/2006: If the last mining counter is removed from Gemstone Mine in some way other than activating its ability (such as Chisei, Heart of Oceans), Gemstone Mine won't be sacrificed but its ability can't be activated.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern