Light orb

Light orbs can be used to fix magical lamps in Dorgesh-Kaan, by using an empty light orb on a piece of Cave goblin wire. Creating one gives 104 crafting experience fixing a lamp gives 1000 firemaking experience.

At level 78 Thieving, it is a potential loot from the Dorgesh-Kaan - Rich Chest.

Light orb is the actual ingame name which is also used in the Grand Exchange. It is known as Dorgeshuun Lightorb in the Knowledge Base and Statistics screen of the game Interface.