Yes, there's been some research in this area, though it's still quite nascent compared to other piezoelectric applications.
**What exists:**
A March 2025 paper in Scientific Reports investigated a hybrid system integ [Nature](https://www.nature.com/articles/s41598-025-95213-5) rating piezoelectric and geothermal properties of basalt and quartz stones to generate electricity, noting that quartz and tourmaline show piezoelectric properties when subjected to mechanical stress or natural vibrations, such as seismic activity or mechanical pressure. This appears to be one of the first studies specifically coupling geothermal heat storage with piezoelectric harvesting from natural stone.
Earlier foundational work from 1981 (Bishop's paper in Tectonophysics) established that quartz-rich rocks like quartzites, granites, gneisses, and mylonites do exhibit measurable piezoelectric effects when stressed, though rocks with little free quartz like marble and basalt did not show significant effects. [ScienceDirect](https://www.sciencedirect.com/science/article/abs/pii/0040195181902687)
**Related findings:**
Recent 2024 research in Nature Geoscience demonstrated that stress on quartz crystals can generate enough voltage to electrochemically deposit gold from solution [Nature](https://www.nature.com/articles/s41561-024-01514-1) during seismic events—proving that natural piezoelectric voltages in underground quartz are real and geologically significant.
**Key challenges:**
The research identifies several issues limiting practical underground piezoelectric harvesting:
- Studies on the efficiency of natural stones in generating electricity from mechanical stress are sparse, and scaling piezoelectric systems for continuous energy generation remains a technical challenge. [Nature](https://www.nature.com/articles/s41598-025-95213-5)
- Piezoelectricity requires *changing* stress (dynamic loading), not static geological pressure
- Natural crystal orientations in rock are often random, which reduces net output
- Synthetic materials like PZT ceramics vastly outperform natural quartz
There's also work on piezoelectric harvesters for downhole drilling operations, but these use engineered materials rather than harvesting from the rocks themselves.
So the concept is being explored, but it's early-stage. Most piezoelectric energy harvesting research focuses on surface applications (roads, railways, wearables) where you can control the materials and stress conditions.