ABSTRACT Boron is an essential element for the development of life on Earth; borates stabilize ribose in prebiotic reactions and facilitate metabolism in higher plants. There is, however, a relatively narrow surface boron concentration range over which borates stabilize and serve as a micronutrient rather than a toxin. That life evolved to utilize borates suggests that the boron concentration in surface waters must have remained relatively stable over much of Earth's history. Here we show that natural tourmaline nucleation is facilitated by epitaxy on the mica minerals; common constituents of peraluminous continental crust. By reducing the kinetic barrier to tourmaline nucleation, epitaxy has helped to enable the long‐term sequestration of boron within Earth's continents and has helped maintain a stable abundance of bioavailable boron going back at least ca. 3.7 Ga.
Dyck et al. (Mon,) studied this question.