The authors have developed the method of calculation of thermodynamic properties of natural and artificial minerals, which is an effective complement of labor-intensive and high-cost experimental studies. This method makes it possible to calculate with sufficient accuracy the chemical composition of stoichiometric formulas, enthalpy, Gibbs energy, entropy and heat capacity values of previously unexplored compounds. These parameters are necessary to determine the conditions of formation of these components and possible ways of further use in technological processes.The aim of the research is to compare the capabilities and features of applying the calculation methods of thermodynamic properties using regression analysis and minimization of free energy on the example of alkaline silicates and clay minerals and to compare the obtained values with the experimental data.The methods: two basic methods for determining thermodynamic properties of compounds: regression analysis based on the classical additive Neumann-Kopp method, and calculation by minimizing free energy using the model of ideal solid solution (program complex “Selector”). The results. The authors have calculated thermodynamic properties using regression analysis. The paper demonstrates a good correspondence of the experimental data, based on the literary sources, and calculation of the values of enthalpy and entropy of formation for alkaline silicates. The calculation of thermodynamic properties by minimizing free energy and the model of ideal solid solutions of mixed-layer aluminosilicates allowed determining the summary stoichiometric formula, Gibbs energy, enthalpy of formation and entropy of montmorillonites and chlorites by chemical composition. The obtained values are comparable with the results of melt calorimetry of dissolution and reference data in accuracy. The results showed that the chemical composition of monomineral fractions is not ideal. The refore, if the mineral formula is known in advance, the calculation of thermodynamic properties by minimizing the thermodynamic potentials is more convenient to perform on the stoichiometric formula, correcting the list of minals of the solid solution.