Titanium dioxide can form several different shapes, which have different properties. Some shapes can be converted to nanomaterials. Micronized TiO2 (also called “nano” or “nanoparticles”) was introduced in the early 1990s.Nanotechnology and micronization both refer to the practice of creating very small particles sizes of a given material. “Nanoparticles” usually refers to particles smaller than 100 nanometers; a nanometer is 1/1 billionth of a meter. At these small sizes, and at low concentrations, titanium dioxide appears transparent, allowing for effective sunscreens that do not appear white.