The ancient crystal is a drop obtained from revenants found in the Revenant Caves.
Four of these, along with four marble blocks and level 80 Construction, are required in order to build an obelisk in the Superior Garden of a player-owned house.
Dropping monsters
Monster Combat level Quantity Rarity Revenant imp 7 1 Rare Revenant goblin 15 1 Rare Revenant pyrefiend 52 1 Rare Revenant hobgoblin 60 1 Rare Revenant cyclops 82 1 Rare Revenant hellhound 90 1 Rare Revenant demon 98 1 Rare Revenant ork 105 1 Rare Revenant dark beast 120 1 Rare Revenant knight 126 1 Rare Revenant dragon 135 1 Rare
