The Revelation ability, which is unlocked in the Assassin ability tree, lets you detect nearby objectives and other important items. It’s one of the first three abilities, so you can get it the first time you level up, and you should. Use this to find loot for easy identification. It is especially useful when making your way through dark areas like caves, ruins, and tombs. This ability has no cooldown, so you can use it as often as you like.
Assassin's Creed Odyssey eGuide The Essentials