<p>This study investigated the physicochemical and mineralogical properties of soils used in earthen constructions, with the aim of characterizing the materials of the main types of earthen construction and their source soils from a soil science perspective. Samples from vernacular and modern constructions, together with those from adjacent soils were analyzed, covering traditional techniques such as adobe and rammed earth, as well as compressed earth blocks (CEB). Particle size analysis by sedimentation revealed that vernacular constructions exhibited textural distributions more closely aligned with the optimal ranges reported in the literature with clay, silt, and sand contents that favored cohesion and workability, whereas modern constructions showed greater variability, particularly in the sand fraction, which may result from the mixing of materials. Statistical analyses, including T-tests, one-way ANOVAs, and a MANOVA, did not detect significant differences (<i>p</i> &gt; 0.05) in the particle size fractions (clay, silt, and sand) between construction types or origins, although trends toward higher silt content in vernacular constructions were observed. Furthermore, organic matter content was lower in CEBs, reflecting the greater selection of purely mineral raw material in these structures to ensure their stability. Altogether, these findings indicated that while trends exist in the chemical and textural composition of materials used in vernacular versus modern constructions, soil selection largely depended on local availability and empirical knowledge. Finally, their properties were assessed in relation to their suitability as construction materials.</p>