Modern technologies offer nowadays a great variety of solutions for soil stabilization, as low- or high-pressure injections of fluid mixtures. There are many different products suitable for this purpose, depending on the properties of the soil to be treated: for sand, in particular, suspensions of nanoparticles, made available by modern industrial technologies, can be considered among the fluid mixtures potentially suitable for its treatment. This work presents the preliminary results of a wider study developed to verify the potential beneficial effects of the injection of natural based micro- and nano-materials on the mechanical properties of coarse-grained soils. To verify the improvement in sand strength, standard geotechnical tests, such as direct shear tests, were performed on soil samples before and after the injection of micro- and nano-particles of natural materials (sand, clay and graphite). The results proved that the injection in sand of a mixture of water and micro-sized sand improves the mechanical characteristics of the samples. By adding clay nanoparticles and graphene to this mixture the results showed an even greater increase in the shear strength. The results of this work proved that natural based micro- and nano-materials seems to have promising properties to become a competitive resource in the field of geotechnical engineering as soil stabilizers, as a valid alternative to widely used materials.