reaction texture

Reaction textures in geology describe features that indicate a mineral has been partially removed or altered by reaction with magma or other fluids. This can manifest as corroded crystal margins, where one mineral is rimmed by finer-grained aggregates of another. These textures provide valuable insights into the chemical and physical conditions under which rocks formed and evolved. For instance, observing a corroded garnet surrounded by a rim of cordierite suggests the rock underwent decompression at high temperatures, with the process occurring too rapidly for complete recrystallization.123