Tourmaline Stability Linked to Boron Levels in Hydrothermal Fluids

A recent experimental investigation clarified how much boron is needed for magnesium-rich tourmaline to crystallise under hydrothermal conditions, providing new insight into the formation of this prized gemstone.¹

The paper, authored by Julien Fort, Stanislas Sizaret, Michel Pichavant, Arnault Lassin, Johann Tuduri, and Olivier Blein, appears in volume 38 of the European Journal of Mineralogy, spanning pages 635–654, and was published on 20 October 2026 at 22:21:55 +0200 UTC.¹

Using high-temperature experiments, the researchers determined that the minimum boron concentration rises with temperature: about 2 wt % B₂O₃ at 400 °C increasing to roughly 3.4 wt % B₂O₃ at 600 °C.¹ Thermodynamic models reproduce this behavior; however, the values show a mismatch if not refined to account for the chemistry of the experimental results.¹ These constraints help predict natural fluid–rock interactions and ore deposit formation.¹