The Bay of Fundy has the highest tides on Earth, up to sixteen metres, and twice a day they scour the basalt cliffs of the Nova Scotia shore and drop amethyst, agate and zeolite crystals onto the beaches. The shore around Parrsboro and Cape Blomidon (in Mi’kmaq legend the home of the god-hero Glooscap) is a famous rockhounding coast; you walk the tide line for what the sea has just unpacked. PUBLIC foreshore below the tide line, but mind the tide, it comes in faster than you can run.
Amethyst, agate, zeolites
See it on the map
Other places on the map within a couple of hours.