In this research, four types of clays collected in the locality of Puno (Perú) were studied and evaluated as potential raw materials for geopolymeric mortars (binder-fine sand mixtures). The actual density of the clays was determined and then a matrix of mixtures was elaborated, considering for all cases a volumetric ratio of 1:3 binder-fine sand. In the manufacture of geopolymer mortars, Na(OH) solution with molarities of 8, 12 and 16 was used as the hardening phase liquid. The binder:liquid phase ratio was 0.6 and in parallel, conventional Portland cement mortars were manufactured for comparative purposes. This study focused on the mechanical evaluation in compression of the manufactured mortars, finding for all cases, a systematic increase in the maximum average strength as the molar concentration of the liquid phase increased. The geopolymer clay mortar that showed the best mechanical results was the one that used gray clay as a binder and Na(OH) solution concentration of 16 molar, the average maximum compressive strength, stiffness and porosity values found were 70.5 MPa, 11.75 GPa and 17.7%, respectively. For reference, the average maximum compressive strength, stiffness and porosity values found for Portland cement mortars were 38.8 MPa, 8.8 GPa and 30.8%. Microstructurally, Portland cement and geopolymeric mortars presented similar characteristics with two well differentiated phases, one of dispersed fine sand and the other of a binder that enveloped the fine sand phase.