In college I had a work-study job for some geology grad students
[Dave, if you are out there, I know I owe you $25.]
I used to grind basalt into a very fine powder as preparation for neutron spectroscopy. I know that "gunpowder-like smell", very well. And yeah, when I left the lab from 4 hours of grinding, no matter how careful I had been, it was time for a shower.
