The Archon's Dream is a very valuable gem found in a chest during The Archaeologist. You can either give it to Belle or keep it for yourself by killing her. It has no real use for the player other than a gift or to sell for a large sum of gold. It has the same picture as an Amethyst.
Description
One of the three Divinity Gems, the most precious jewels in all the Old Kingdom. It is said that this one was presented to Archon in a dream, as a gift from the gods. After the destruction of the Old Kingdom, the gems were scattered throughout the world, and though they have often been dismissed as nothing more than legends, thousands have devoted their lives to finding them.