Symmetry-based electricity in minerals and rocks: A summary of extant data, with examples of centrosymmetric minerals that exhibit pyro- and piezoelectricity

Abstract

The Earth's core, mantle and crust are composed of rocks and minerals, and exhibit electrical and magnetic phenomena. Electrical data in particular are extremely sparse for Earth materials; fewer than one hundred minerals have piezoelectric data associated with them, for example. More data would help to constrain Earth processes and structures, such as core and mantle composition, geomagnetic anomalies, seismic electric signals, and others. Herein, two hundred seventeen minerals exhibiting ferroelectricity, pyroelectricity or piezoelectricity are presented, with quantitative data where known. Fifty-three of these are centrosymmetric, and explanations are given for their apparent violations of crystal theory. Some thermoelectric and magnetic data are also presented for minerals, and an overview of rock electricity is included. Recommendations for further study are given, as well, such as determining the dielectric behavior of rocks and minerals at depth, and testing minerals for alternative energy applications.