A natural Al silicate nanotube is the halloysite. Halloysite is a dioctahedral 1:1 phyllosilicate similar to kaolinite with no significant charge and high adsorptive properties. The siloxane surface is oriented to the external part of the tube whereas the aluminol surface is oriented to the internal part of the tube. Its main morphology is the tubular one, formed by concentric tubes with layers of internal tetrahedral silicate sheet with internal octahedral sheet. The lengths of halloysite tubules cover a wide range from 0.02 to >30 µm, while their widths range from <0.05 to 0.2 µm. These nanotubes have high absorption properties for drugs. However, the formation mechanism of this mineral is not well known yet.