How to properly tag small rock formations, like
http://pl.wikipedia.org/w/index.php?title=Plik:Sklane_grzyby.JPG
http://en.wikipedia.org/wiki/Maczuga_Herkulesa
http://www.tenpieknyswiat.pl/fotki/albums/20060603_Karkonosze/pict0758.jpg ?
Seems that natural=stone is a more common tag than landmark=large_rock.
landmark=rock_pinnacle, maybe? At the moment there’s just one object carrying that tag in OSM.
Your third example looks a bit like what the South Africans would call a “Castle Kopje”. I’ve used “natural=castle_kopje” for one of those in Derbyshire, but it’s the only one in Taginfo. Despite being English I’ve no idea what the native English term for something like this would be.