I spent the better part of this afternoon polishing the smudges off my smartphone screen

Most folks see a window into the digital world, but I see a feat of geological engineering called Indium Tin Oxide. It is a strange, transparent conductor that allows your fingertips to talk to the machine, yet you will rarely find a dedicated indium mine anywhere on the map. We get it as a byproduct, mostly squeezed out of the zinc ores found in places like the red-rock canyons or the deep underground deposits of the Pacific Northwest.
Every time you swipe a screen to check the weather or send a note, you are touching a microscopic layer of the earth that had to be refined through a dozen complex chemical stages. It is a funny thing to realize that our highest technology is entirely dependent on the scraps left over from base-metal mining. Without those trace elements hidden in the dross, we would be back to using buttons and dials in a hurry.