Gemstone Mine enters the battlefield with three mining counters on it.

{T}, Remove a mining counter from Gemstone Mine: Add one mana of any color. If there are no mining counters on Gemstone Mine, sacrifice it.

Return target card from your graveyard to your hand.

{T}: Add {C}{C}.

{T}: Add {C}.

{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.

{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.