The brooch is an item that is obtained during The Lost Tribe quest. Players can find it at the first fork of the Lumbridge Castle cellar caves, heading towards the Dorgeshuun Mines. This item does not have a respawn time - it immediately appears on the ground right after it is taken.
Players must bring the brooch to Duke Horacio. After looking through the Goblin book, the player finds that the brooch belongs to the lost Dorgeshuun goblin tribe, as it bears the symbol of the tribe.
After the quest, the brooch can be given to Mistag in exchange for a mining helmet. The brooch is otherwise useless.