Are we allowed to pick rocks/shells/driftwood from beaches and rivers?

I got yelled at by an old lady recently because she saw me picking up some shells on the beach. I wasn't even collecting a bag full of them or anything, I literally had a small handful of some pretty ones from near the shoreline. I also don't even go to the beach that often, maybe only once a twice a year with my family. We also like to go to rivers and we might pick up a few nice rocks or pieces of driftwood from there too to decorate our fishtank at home.So, what exactly are the rules around picking up stuff from public areas like beaches and rivers? Any insight would be appreciated because I don't want to be committing any crimes or getting accused of crimes I might not be committing. via /r/newzealand https://ift.tt/3mgGWvV