A Hidden Treasure - Side Quest Act 2
Start Location: Fayum Oasis
Quest Location: Mysterious Tomb in northern Fayum Desert
Objective: Find the treasure room inside of the tomb
A Hidden Treasure begins by speaking with Asri in Fayum Oasis. He asks you to search a tomb that is north of the city, the exact location is shown in my screenshot below. All you need to do is enter the tomb and find the treasure room, once you enter the treasure room the quest will automatically complete.
Just south of the tomb you can find Iznu, a named who is involved in the Caravan Woes Side Quest. Defeat him on your way here to complete two quests at once.