Your search for "Powerstone Minefield 115" revealed the following:
Powerstone Minefield (Foil) (APC) from Apocalypse, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: Greg Hildebrandt Card Text:Whenever a creature attacks or blocks, Powerstone Minefield deals 2 damage to it.
Powerstone Minefield (APC) from Apocalypse, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Greg Hildebrandt Card Text:Whenever a creature attacks or blocks, Powerstone Minefield deals 2 damage to it.
Powerstone Minefield - APC Reprint (PLST) from The List, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Greg Hildebrandt & Tim Hildebrandt Card Text:Whenever a creature attacks or blocks, Powerstone Minefield deals 2 damage to it.