Rock is often used to symbolize permanence, yet the structure of rock is constantly evolving, often on a spatial scale too small and a time scale too long for us to easily appreciate. By viewing cross-sections of sedimentary stone through a microscope, we can read the history of its incremental formation like the rings of a tree.
Here, this technique has been applied to a kidney stone that spontaneously formed in the body of a patient. Scientists were able to rewind the process through which three stones fused together to make one. By merging the geological knowledge of rock formation with the medical science of kidney stone prevention, they have developed a powerful new approach for addressing a common and painful disease.