Theories abound about the purpose of Stonehenge and why the stones used there came from over 200 miles away. Now there's a new hypothesis: the rocks used at Stonehenge may have been selected because of how they sounded. Sound specialist Jon Wozencroft was part of a team with the Royal College of Art in the UK that examined the site, and described banging on the rocks of Stonehenge.
Lithophonic stone—also known as ringing rocks—can be found all over the world, including at the site where the Stonehenge bluestones were quarried.
Nobody knows why these rocks ring. There’s a ringing rocks park in Pennsylvania and researchers from the University of Pennsylvania even examined a slice of one, but couldn’t figure out how the sound is made.
The stones make a whole range of sounds, and you don’t have to hit the stones hard to hear them. You can create the sound by hitting them about as hard as you would hit a ping pong ball.
Video of Ringing Rocks
Wozencroft says that there are indentations on the rocks indicate that pre-historic men and women knew that the rocks could make sounds. If they weren’t used as an early musical instrument during rituals, he says that these ringing rocks could have been used as signals because you can hear the sounds half a mile away.
The theory was first mentioned in the 1950’s, but no one’s followed through on it, until now.