Aluminium oxide nanoparticle
Nanosized aluminium oxide (nanosized alumina) occurs in the form of spherical or nearly spherical nanoparticles, and in the form of oriented or undirected fibers. == Properties == Properties, of the final material, defined as the set of properties of the solid aluminium oxide and specific properties of nanostructures.
Source: Wikipedia — Aluminium oxide nanoparticle (CC BY-SA 4.0)