Four rough stones ready to tumble! Each stone is approximately 1 inch. Goldstone is soft: a Mohs hardness scale of only 5.5-6 will require fewer days in the rock polisher.
Goldstone is actually not a rock but a specialized glass product that may have been invented in the 1100s in Persia. Its deep color and internal sparkle have been highly prized for jewelry.
A perfect gift for the rock hound in your life. If they don't already have a rock tumbler, you're in the right place. The Science Museum of Minnesota also sells tumbling supplies and equipment.
