User blog comment:Scooter8pie/Alchemy and the Brown Mob/@comment-4583259-20111125192654

I got a brown mob in one of my astronaut test pits (the one made for this picture: File:Diffusion-gradient.jpg ) so I trapped it and eventually built an alchemy cube by your method. I put refined aluminum in the top two layers (I wanted Molybdenum but was confused).

Later I made my map program create cross-sections, so here is a cross section through the middle of my brown mob explosion:



I made the cube 11x11 horizontally, and 10 blocks high. The mob had 5 layers of gold under it when it exploded, which turns out to be higher than I wanted.