Physical properties of a natural lamellar aluminosilicate structure, rich in Fe

► We studied a natural sample from the coast of Sergipe, state of Brazil, with a lamellar aluminosilicate structure. ► The three major components are phlogopite, clinochlore and goethite. ► The ferromagnetic behavior was found at room temperature with TC>300 K. ► The inverse susceptibility as a function of temperature was fitted with the theoretical model applicable to ferrimagnetic materials.