Gameplay

Sacred Icon (achievement)

From Halopedia, the Halo wiki

Were you looking for the Halo 2 level, Sacred Icon (Level), or the Activation Index?
Sacred Icon

Sacred Icon is an achievement in Halo 2 for Windows Vista, and Halo: The Master Chief Collection. In the PC game it is worth 30 Gamerscore and is unlocked by beating Sacred Icon on Normal, Heroic, or Legendary. In The Master Chief Collection it is only worth 10 Gamerscore, though it can also be unlocked on Easy.

In the PC game, it is represented by the activation index that the Arbiter is tasked with acquiring at the start of the level. In The Master Chief Collection it is represented by a screenshot of the first room of the level.