Mineral samples from two geological formations (Guayabo group (AGG) and Carbonera formation (AFC)) of northeastern Colombia, rich in phases of the clay group, were characterized to clearly know the types of phyllosilicates present, their microchemical and morphological characteristics, its cation exchange capacity and specific surface area; Similarly, identify the other mineralogical phases present in these materials. Different techniques such as X-ray diffraction and fluorescence, Fourier transform infrared spectroscopy and scanning electron microscopy with X-ray dispersive energy analyzer were used in the process. The results obtained allow us to be certain that the kaolinite phase is present in both clay samples (AGG and AFC), the lamellar crystals observed and associated with this mineral have a high silicon content, according to the FTIR analysis, this could be due to the existence of more than one phase in them. In the same way, it was possible to demonstrate the existence of a mineral from the group of lamellar-type micas. The thermal evaluation carried out led to the suggestion that it is the Muscovite phase. More abundant lamellar crystals, chemically formed by silicon, aluminum, potassium, and iron, were associated with this last mineral, also highlighting a high silicon content. The crystals of the AGG sample stand out for being larger than those of AFC and for having a higher potassium content. The cation exchange capacity is higher in the AGG sample (11,5meq/100g) possibly associated with the higher muscovite content, while in the case of the surface area there were no significant differences, obtaining values close to 30 m2/g, slightly higher values to those reported for soils with the presence of kaolinite.
