Extraction

Lead and silver come from the same rock. This is the fact I return to when people ask me why I study geology instead of something useful. Galena. Lead sulfide. PbS. Grey, cubic, heavy in the hand. Cleaves along perfect planes — break it and you get smaller cubes, each one a mirror of the whole. The Greeks knew this. The Romans smelted it for pipes and died young, though they blamed other things. The silver hides inside. One to three percent, locked in the crystal lattice, invisible to anyone who doesn't know it's there. You have to heat the lead to six hundred degrees and the silver separates — rises to the surface and can be skimmed off like fat from broth. Cupellation, the process is called. From cupella, a small cup. The Romans did this too. Their silver coins contained the ghosts of lead. My professor told us transformation always costs something. She meant thermodynamically. She meant energy input, entropy, the second law. I think she also meant the other thing — that you can't become what you need to become without losing the shape you were comfortable in. I held a piece of galena on my first day of fieldwork in Sardinia. Heavy. Cold. Perfect on the outside. Containing silver I couldn't see. I'm still in the program. I still don't know if I'm the lead or the silver or the heat. I suspect I'm the cup.