Rock Doc

The next time you have a saltshaker handy, you might want to remove a few grains. If you have a simple magnifying glass, you’ll see the salt is really tiny cubes. Salt is a mineral and each grain is a well-formed crystal that breaks into cubic shapes.

Salt in your saltshaker looks like a simple solid, just another bit of sturdy matter that doesn’t flow or deform. But salt that’s under pressure is different. Salt far enough underground behaves like Silly Putty, oozing and flowing over time.

Salt has been on my mind recently because I’ve been reading about nuclear energy. Bear with me and I’ll e...