According to my research, if a magical stone is set in metal that's empowered with the same type of magic as the stone it holds, it should be possible to attune the container so it hides the power of the stone within. I can do the forge work, but I'll need the help of the glaufaye for the magic.
Steps[]
Exit the city to Thalumbra and discuss the recipe with Elanluelle ( -486, 240, 349 ) Copy/waypoint -486.30, 239.76, 349.24 in Zou'Lidelas.
Return to Maldura and forge the Censer of Containment in the great Forge of Brell ( 68, -8, -132 ) Copy/waypoint 68.02, -7.68, -131.54. (Note: Be careful not to miss any counters! They will kill you, put you back at entrance, and you will have to start over (rares not lost.)
Exit the city to Thalumbra and speak to Elanluelle at ( -486, 239, 349 ) Copy/waypoint -486, 239, 349 again:
Note: make sure you finish the conversation before you start to craft the Empowered Censer of Containment! If you forge the item before getting instructions to do so, the quest will not update and you have to delete and start over and you have lost your 2 Arcannium!
Click the Fire in front of Elanluele after the quest updates from speaking to her.
Reforge the item. Will need 1 bornite nodule and 1 Thaumic Coal.
Once that is completed, speak to her once more to update the quest.
Bring the completed censer to Brytthel in Maldura at ( 371, 82, 29 ) Copy/waypoint 370.65, 82.35, 28.72.