Abstract Clay and associated minerals were identified in lateritic-bauxitic samples using a combination of pretreatment and instrumental techniques. The minerals included kaolinite, palygorskite, gibbsite, goethite, hematite, and chlorite. Size fractionation played an important role throughout all pretreatment stages, which varied from chemical treatment of the surface phases in the rock chips to extraction of the fine fractions of the samples with a strong alkaline solution. Samples were examined by thermal (TG, DTG, and DTA), X-ray diffraction, and IR-spectrometric methods. Each instrumental technique played an important role in the characterization, but positive identification of some minerals was possible only when all the techniques were used in a complementary way.