Just this summer I noticed that the magnets on the back of my barbecue thermometer were picking up a lot of magnetic sand from the local riverbank. I went back

Just this summer I noticed that the magnets on the back of my barbecue thermometer were picking up a lot of magnetic sand from the local riverbank. I went back with a super-duper magnet-fishing magnet and found that probably 20% of the rocks there were magnetic. I've explored a little bit, and (mind blown) there are magnetic rocks all over the place, from cliff sides to rocks in my front yard to gravel from my friend's driveway. I haven't looked anywhere outside of Oregon and Washington though, but it seems like rocks with significant (presumably)-iron content aren't rare at all.