The clay studied is taken from Guayaquil, Ecuador. It belongs to the Ancon Group, is Middle to Late Eocene Age and stems from change via Andean volcanic ash neoformation. In 32 collected samples, the three main granulometric fractions contained were quantified. Difraction via X-Ray analysis was carried out and the chemical composition was quantified. This allowed for the obtaining of an initial knowledge of the mineralogy and of the largest chemical proportions. It further allowed us to select 13 representative samples. In the clay fraction, X-Ray difractograms of samples saturated in MgCl2, KCl and LiCl enabled us to establish the group and species of the abundant clay mineral, thus identifying the montmorillonita. Five samples -containing a greater proportion in clay minerals and in clay fraction-were chosen and their ionic interchange capacities, together with their main cation, were quantified.. Density and specific surface quantifications, plus thermal analysis, infra-red spectroscopy, and microscopia electronica de barrido, allowed us to obtain greater details as regards the physical, mineralogical and morphological characteristics. With the total of results obtained, it was possible to conclude that we were dealing with a calcium bentonite clay. Acid activating tests showed that it is possible to obtain chemically modified clay which might be used in the new industries, beside using the present-day cement and ceramic which have their traditional, small-scale uses.