Are there usually sharp pebbles in potatoes?

[Saikii]

I made some for myself earlier and there were two or three really sharp, but tiny pebbles of something I couldn't eat. I tried to catch them and they scratched up the roof of my mouth before I got a hold of them. I had made oven roasted potato wedges using a knife and an apple slicer to eat with my microwave popcorn chicken. Neither of those tools were broken or rusty. The pan was fine. The potatoes themselves had a few root sprouts, but I removed those before washing them.

They do kinda grow in the ground. I've never heard of the spuds having shards of pebble that far in the potato, though. Good thing I caught em. >.>; That could have been dangerous.

I still don't fully understand what went on there.  

[chessiejo]

i grew up in potato country, there were four major farms each with at least 500 acres under cultivation.

they grow best in muck. one local brand is even "muckland". so, there are few stones. these were all white potatoes, the kind you mash or put in stew, not for baking or fries.

maybe those other kinds of potatoes have more stones?