Rock Doc

When I was a younger and more sprightly woman, I spent part of my life investigating unusual hot springs in rural California. They were salty and quite stinky springs out in the middle of nowhere, and several of them occurred right in the center of an old gold-laced mercury deposit.

No one was actively mining the small area where the springs are found – there just wasn’t enough ore to make the project economic. But the rocks of the location had small veins of chalcedony, calcite and other minerals that had elevated values of both gold and mercury in them. Working with a couple of colleagues, I...