Chaos tiaras are made by using a tiara on the chaos altar with a chaos talisman in player's inventory. By doing this they will earn 42.5 Runecrafting experience. It serves the same purpose as the talisman or a chaos talisman staff, but cannot be used to locate the altar and is worn on the head slot. It has no combat bonuses.
A chaos tiara can be worn in the head slot, allowing players to left click on the altar to get inside, saving them an inventory space.