Piezoelectric effect in renal calculi

The piezoelectric effect was investigated for the first time in renal calculi in vitro. The kidney stones were shaped from solid samples as well as from stones crushed into powder and pressed into tablets. The dissipation factor and dielectric loss factor of the solid stone specimen are found to be higher than that for the powdered stoned tablets. The major constituents in the calculi are calcium oxalate, calcium phosphate, uric acid, and alpha-quartz (a new finding). The presence of alpha-quartz helps to explain the piezoelectric property of the kidney stones. The piezoelectric voltage developed would assist in fast disruption of stones.