These sort of datasets is not surprising to see. I watch "how it's made" videos on youtube and a lot of factory processes seem to have computer vision based sorting for rejecting rocks, debris, etc.
One of my professors consulted for Del Monte. They had an automated vision system that could spot damaged corn kernels as they flew down the conveyer belt and precisely knock them off into a hopper with a puff of air.
I have a small collection of bean-shaped rocks that I have found over time in my purchases of dry beans. Lesson, rinse and sort your beans! By sort I mean remove a 2-3 shrivelling beans per pound and a rock every 10 lbs.