The question about the harmfulness of electromagnetic radiation is ever more often raised in scientific discussions it is also interesting for the public. Unfortunately, there are no easy answers and no settled opinion. Followers of the catastrophic vision of the future argue, that the electromagnetic smog never grew as fast as today, and our bodies are probably not prepared for such conditions. Opponents, being accused of favoring telecommunication companies, claim that there are (or were) enough sources of electromagnetic radiation in the natural environment for organisms to learn how to self-protect, either by adaptation or development of specific sensory mechanisms. Questions are raised not only about health aspects, but also about security of data transmission and possible military applications, such as protection against radar localization. We want to present our recent investigations about the uses of natural materials for suppressing electromagnetic waves. The materials in question are ordinary clays, which role in Nature is barely now being discovered. Clay minerals, the basic ingredient of clay, are unusual materials, formed by Nature into nanostructures. Just recently we have begun to understand their role, behavior and possible applications. Those minerals, especially kaolinite and halloysite, are widespread, but in pure form occur only in few places in the world. Polish deposits belong to the richest ones.