It is important that pastes and creames for skin treatment have suitable rheological properties and ability to establish a good contact with the tissues while retaining their tightness. Thixotropy is desired for providing fluidity when agitated and a suitably degree of stiffening thereafter. This requires low shear resistance in the coating phase and microstructural reorganization when leaving the paste to rest. Following the principle of using only mineral components for skin treatment, use of expandable hydrophilic clay minerals should be considered. They sorb cations and positively charged organic molecules and are impermeable to fluids and gas under low pressure, hence providing oxygen-free micro-environment. They can balance pH and are excellent agents for cleaning skin.
 Arnold, D.E. (2005) Maya Blue and Palygorskite: A Second Possible Pre-Columbian Source. Ancient Mesoamerica, 16, 51-62. http://dx.doi.org/10.1017/S0956536105050078
 Pusch, R. (2008) Geological Storage of Radioactive Waste. Springer Verlag, Berlin and Heidelberg. http://dx.doi.org/10.1007/978-3-540-77333-7