  Recent studies on metamorphic petrology as well as microstructural
observations suggest the influence of mechanical effects upon chemically active
metamorphic minerals. Thus, the understanding of such a coupling is crucial to
describe the dynamics of geomaterials. In this effort, we derive a
thermodynamically-consistent framework to characterize the evolution of
chemically active minerals. We model the metamorphic mineral assemblages as a
solid-species solution where the species mass transport and chemical reaction
drive the stress generation process. The theoretical foundations of the
framework rely on modern continuum mechanics, thermodynamics far from
equilibrium, and the phase-field model. We treat the mineral solid solution as
a continuum body, and following the Larch\'e and Cahn network model, we define
displacement and strain fields. Consequently, we obtain a set of coupled
chemo-mechanical equations. We use the aforementioned framework to study single
minerals as solid solutions during metamorphism. Furthermore, we emphasise the
use of the phase-field framework as a promising tool to model complex
multi-physics processes in geoscience. Without loss of generality, we use
common physical and chemical parameters found in the geoscience literature to
portrait a comprehensive view of the underlying physics. Thereby, we carry out
2D and 3D numerical simulations using material parameters for metamorphic
minerals to showcase and verify the chemo-mechanical interactions of mineral
solid solutions that undergo spinodal decomposition, chemical reactions, and
deformation.
