// {tap}: Add {1} to your mana pool. If Gemstone Caverns has a luck counter on it, instead add one mana of any color to your mana pool.
Ability ability = new ConditionalManaAbility(Zone.BATTLEFIELD,
new ConditionalManaEffect(
new AddManaOfAnyColorEffect(),
new BasicManaEffect(Mana.ColorlessMana),
new SourceHasCounterCondition(CounterType.LUCK),
"Add {1} to your mana pool. If {this} has a luck counter on it, instead add one mana of any color to your mana pool."),
new TapSourceCost());
this.addAbility(ability);
}