anybody who owns a volcano

Hey, I have a volcano, and I might have lost a part, but I'm not sure. Can somebody take a picture or describe really well what the bottom of their filling chamber looks like?

My filling chamber isn't sitting level on the top of the volcano, and I want to see if there is a missing part, or what happened. I just went to my friends house, and the last place I used it was there, so I can't easily look around for anything odd...

Mine is all silver, except for the black edge and screen.

Thanks for any help guys. It still works, but now it is a lot more work and annoyance.

Nevermind, I found what I need to find. It is a little rubber o-ring.