A study was conducted on the site of the Institut des Nouvelle Technique Agricole d 'Azaguié in order to understand the role of minerals in assessing the level of soil evolution. To this end, a study of different soil fractions was carried out. Thus, a mineralogical study of the sandy fraction was carried out by sorting on a sieve column. Whereas the mineralogy of the total soil and the clay fraction were determined by X-ray diffractometry. The results obtained under this study reveal that in the sand fraction, quartz (over 50%) is the most abundant mineral at all topographic levels whereas iron oxides (hematit and martit) are observed only in mid and lower slopes. In total soil, clay (kaolinite, antigorite, montmorillonite-chlorite) is observed at 4-19 %, oxides (goethite, quartz) with 67-91 % content and primary minerals (muscovite, feldspar) to 5-14 %. Whereas the clay fraction is only provided with kaolinite type clay (over 80%), smectite, chlorite and interlaminated (chlorite-smectite and illite-vermiculite) at about 5%. These soils are highly advanced due to their high kaolinite and mineral content, such as quartz and also the presence of hematite, goethite and martite. These mineralogical characteristics expose the soil to a depletion and a firing.