Despite the great interest in the PGE, the thermo-chemical basis of their geochemical properties
remains unclear. Thermodynamic data for PGE-minerals (PGM) are very limited, due probably to
experimental difficulties and very limited data on the activity-composition models and relevant phase
diagrams [21–28]. Assuming that the required thermodynamic data (enthalpy, entropy, Gibbs free
energy) of the reactants and physical/chemical conditions (P, T) are available, then the mineral Gibbs
free energy can be calculated [26–28]. This paper focuses on: (1) the calculation of the Gibbs free
energy of formation for the selected PGM in PGE-bearing complexes worldwide, at standard state
conditions (DfG), using the current state of knowledge from experimental data on the PGE; and (2) the
application of the calculated Gibbs free energy (DG) values to predict the stability of PGM