These Pennsylvania Rocks Actually ‘Sing’ — And Scientists Still Can’t Fully Explain Why

In Bucks County, Pennsylvania, Ringing Rocks Park features unique diabase boulders that produce bell-like tones when struck. Formed 200 million years ago and fractured by Ice Age freeze-thaw cycles, these rocks possess a rare combination of dense composition, internal stress, and specific positioning that allows them to resonate. Scientists believe this geological interplay creates a natural instrument within the forest.