The transformations of clay minerals in Luvisols formed on amphibolite under contrasting semi-arid climates in northeastern Brazil were examined to understand how weathering intensity drives the development of mixed-layer minerals (MLMs) and affects key soil properties. Two Chromic Luvisols, developed from similar amphibolite parent material, each representing distinct climatic conditions (Profile 1: annual precipitation = 415 mm yr-1 transform infrared spectroscopy, thermogravimetry and Mossbauer spectroscopy were used to characterize the clay fractions and their interstratified minerals. The results revealed that both soils predominantly feature interstratified kaolinite-smectite (K-S) phases, with Profile 1 showing higher proportions of expandable smectite layers. In contrast, Profile 2 exhibited a greater enrichment in kaolinitic layers at all depths. Notably, this study demonstrates that the pedogenetic clay minerals in natural Luvisols from the Brazilian semiarid region consist of transitional MLMs rather than discrete endmembers. It also shows that climatic variation influenced the soil mineralogical composition, primarily through changes in the mixed-layer phases. ; Profile 2: = 777 mm yr-1) were sampled across their A, B, and Cr horizons. X-ray diffraction, Fourier-