2 and 3/4 inch Black and White Opal Eater Cave Marble. Caught a small air bubble when encasing the marble and the lenses have a tiny bit of distortion. The distortion is from the layering of the marbles. It doesn’t look bad to me. It just catches the eye when looking at a certain angle. Wanted to be upfront. This is something I’m working on making go away In future pieces. The marble is still pretty awesome to me.