Ringing Rocks of Pennsylvania: A Geological Mystery

By | October 2, 2018

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A woman does Yoga on the edge of a massive boulder field, the remnants of a receding glacier at the end of the last Ice Age, in Pennsylvania on August 2, 2017. (Photo by Cory Clark/NurPhoto via Getty Images)

Most of the time, when you hit a rock, it produces a loud thud noise. But in one mysterious place in Pennsylvania, the rocks don’t thud, they ring. In fact, you’d swear the rocks were not rocks at all but hollowed out chunks of metal. That’s because they sound distinctively bell-like when hit with a hammer. Although the odd rocks were well known to Native American tribes, they have baffled European settlers, scientists and geologists since the first settlers stumbled upon the area in the mid-1700s. Despite years of research, we still don’t know for certain why the Ringing Rocks of Pennsylvania ring. 

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There is a Scientific Name For Ringing Rocks

Although scientists don’t have a definitive answer as to why the rocks ring, they do have a name for ringing rocks. They are called with sonorous rocks or lithophonic rocks. These are the terms that are given to rocks that resonate with a bell-like sound when they are struck.