Power gem in Wormbound Catacombs

[Zo Kath Ra]

In the Wormbound Catacombs, there's a power gem at x=3/y=30/e=-1, behind a mine_door_spear.
You can take the power gem w/o opening the spear door, because clicking on a power_gem destroys it and puts a power_gem_item in the mouse cursor (if it was empty).

This is the only power gem in the game that's directly behind a door.