What Is the Difference Between Rock and Stone?
According to National Geographic, the main difference between rocks and stones, or gemstones, are their rarity and crystal formation. Most gemstones have a crystal formation, which makes them rare and valuable after they are cut. Rocks usually do not have a crystal formation, which means they are not considered to be of value. Unlike rocks, gemstones are classified on their rarity and value into two categories: semiprecious and precious.