We just finished a batch of tumbling which included a few small chalcedony pebbles and agate pieces. These are collected from around Scotland and taken home where we wash and tumble them to a nice shine.
This crystal has a half an eye on it but otherwise doesn't have recognisable agate patterns, we therefore class it as a chalcedony Pebble. This gemstone came from Ayrshire, near where Robert Burns lived. It was picked up, cleaned, and tumbled to a polish in our tumblers.