Equinox

• WWizards of the Coast2004-10-04
  Official Ruling
  Equinox will not counter a spell that has a random chance of destroying a land.
• WWizards of the Coast2004-10-04
  Official Ruling
  Equinox will not counter a spell that deals damage to an animated land, even if it would deal more damage than the land's toughness. This is because the spell itself does not destroy the land directly. The land is destroyed by a game rule.
• WWizards of the Coast2004-10-04
  Official Ruling
  The ability can target any spell, even one that would not destroy a land.
• WWizards of the Coast2004-10-04
  Official Ruling
  Equinox will not counter a spell which would indirectly cause destruction of one of your lands.
• WWizards of the Coast2004-10-04
  Official Ruling
  Equinox will not counter a spell which requires sacrificing land when it enters or one that requires sacrificing land as part of the cost to cast it.
• WWizards of the Coast2008-10-01
  Official Ruling
  Will not counter a spell which would destroy a land only if a choice is made.
• WWizards of the Coast2013-09-20
  Official Ruling
  When the activated ability resolves, determine whether the targeted spell would destroy a land if it resolved right then. If it would, then counter that spell. Otherwise, it is not countered, even if the spell could, under other circumstances, destroy a land.

Rulings via Scryfall