Weapon

Jezirea got down on her hands and knees and began to search through the dust and the darkness, running her hands through the grime to better search for anything that might be useful.
She had almost finished searching when she came upon a sword. It looked old and plain. The hilt was undecorated, but it still looked sturdy, and it would definitely fit the slot in the stone.
Infact, it had probably been what had made the slot in the stone. However, when she took the sword up in her hands, a strange, warm sensation came over her. It wasn't much at first, so she ignored it.
She stood and moved quickly to the alter, and inserted the sword in to the hole.
Nothing happened.

Yeah, that probably meant that the alter had simply been where the sword was placed. It wasn't a mechanism or a key of any kind.

So, she was still somewhat trapped, but now she had a sword. How could that help her?
Perhaps she could use it to pry the doors open, or even to climb out the hole she had entered through.