The availability of the structural micropores in sepiolite for the access o
f molecular or ionic entities is an old and controversial subject, which is
revised in this work in the light of the most recent experimental data obt
ained in our research group. In this way evidence of the accessibility of m
olecules, voluminous ions and polymeric species to the intracrystalline tun
nels of the mineral is presented on the bases of the application of several
techniques to the study of the mineral adsorption properties.