The Archon's Dream is a very valuable gem that you either keep for yourself by killing Belle or give to Belle in The Archaeologist. 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.
The Archon's Dream
Rating: five stars
Base Value: 100,000
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.