Seven pedons were used in a methodical investigation of the weathering and stability of soil minerals of various geomorphic units in the northeastern region of Haryana. The soil minerals were arranged in order of stability, or alternatively, the weatherability of each mineral was forecast using the thermodynamic model that Rai and Lindsay (1975) developed to make generalizations about the behavior of soils, i.e., the physical properties in relation to the types of clay minerals present to evaluate the effects of different environmental conditions on the soil formation process. Plotting the mineral solubility lines in terms of activities of the species common to the minerals under discussion was done using the equation of the chemical species as they relate to the equilibrium constants. Equations demonstrating the link between log (Al+3) and –log (H SiO) for the minerals were created, and stability diagrams were built, in accordance with the methodology described by Rai and Lindsay in 1975.The stability order of various minerals in the study area, derived from the models, was grouped in stability groups (increasing order) for the purpose of weathering stability of primary minerals under various environments: low albite, anorthite, muscovite, microcline, quartz; low albite, anorthite, microcline; muscovite, quartz; anorthite, low albite, microcline, muscovite, quartz; Low albite, muscovite, anorthite, microcline, quartz; muscovite, low albite, anorthite, microcline, quartz. Secondary mineral stability was less variable, with kaolinite, illite, and chlorite having the highest order of stability among the minerals in the various geomorphic units.