The zigzag, staircase, line in the diagram of the periodic table above separates the metals, on the left, from non-metals, on the right. Hydrogen is a non-metal, but it is often put in the middle.

Because it is really over 100 individual displays of the elements, their ores and minerals, and objects made from the elements, it’s more like a museum than a table. So, we’ve taken to calling it the ...