
Explore the rather large, multi-leveled cave. Talk to Zaven, and he will open the door to the Mysterious Cave.
Spawn rate is estimated at 3-5% at each spawn point in Dahlgur Oasis.
Look for Zaven the Alchemist, who must be saved from Deathly Haunts (he does not always spawn, in which case you must leave the game and "Resume Game" to remake). Head southeast until you find a small path leading to a watery clearing (see image in the top left). Make sure the game is set to the seventh (7th - Blood and Sand) or later quest. In Act II, travel to the "Path to the Oasis" waypoint ( Dahlgur Oasis if unlocked by player). This item can be very difficult to obtain, as the procedure is fairly random. Top Left: Location of Cave Entrance (From Path of Oasis waypoint, Act II) Top Middle: The merchant in trouble, you must save him Top Right: After saving the merchant, he will open the door Bottom left: The mysterious chest, looks similar to Resplendent Chest Bottom Middle: Map showing that the chest can be on first (or second) floor, and may even spawn near the entrance Bottom Right: Liquid rainbow item from inventory
Diablo II: Resurrected Review - Pile Of Old Bones