- Talk to Horatius.
- You may have to talk to him a second time to get the quest, and you must have the quest before you can trade him the stone.
- He needs a Dangruf Stone for his gem collection and says they can be found in Dangruf Wadi, of course, but only on sunny days.
- Go to Dangruf Wadi on a sunny day and at I/J-5 location target select the ???, to receive the stone.
- Return to Horatius and trade him the Dangruf Stone for your reward.