Use this artifact on different locations until you find the right one to open the portal that leads to Ani-Dahlia. Quest item for "Searching for the Necromancer" .
Spoiler alert. If you want to know where I successfully used the crystal (without just getting two skellies to fight), take every second letter, starting with the second letter, from the following. It will spell the place name
apiorratooifsstaldrapr
If others have success at the same location, please let us know here.
apiorratooifsstaldrapr
If others have success at the same location, please let us know here.