How can boiling cause minerals to deposit from a hydrothermal solution?

Boiling is one of the primary mechanisms that triggers the precipitation of solids from a hydrothermal solution.

When a hydrothermal solution—typically a hot, mineral-laden brine—undergoes boiling, the rapid transition of the solvent (water) into steam reduces the volume of the liquid phase. This process concentrates the remaining dissolved minerals, eventually reaching a point of supersaturation where the minerals can no longer remain in solution and are forced to precipitate as solids.12

This deposition often occurs within rock cavities or by replacing existing rock structures, contributing to the formation of mineral deposits. While boiling is a significant driver, it is one of several factors that can cause deposition, alongside temperature drops, mixing with cooler solutions, or chemical reactions between the hydrothermal fluid and the surrounding host rock.1