Lustrous Stone from Guyun is Weapon Ascension Materials used to ascend weapons, increasing the stats and max level. Higher-rarity materials can also be crafted with Alchemy by combining lower-rarity materials from the same group.
To the informed, Guyun Stone Forest is not some miraculous sight on the sea to behold, but the cemetery of the former gods of Liyue. Hatred and filth have periodically raised up from it, but all have been subdued by a demon-conquering young man.
How To Get
Lustrous Stone from Guyun is obtainable from crafting and dropped as a random reward from completing the Hidden Palace of Lianshan Formula domain near Mingyun Village every Monday, Thursday, and Sunday.
Lustrous Stone from Guyun can be crafted in the Alchemy table in Mondstadt or Liyue using 3 pieces of Luminous Sands from Guyun.