What is the minimum particle size? April 14, 2021 13:57 Updated Titanium and Zinc oxide are uncoated and have a minimum particle size of 0.1 microns. Related articles Do you use any nano or micronized particles? What is the exact size of the Titanium Dioxide particles in the powder foundation? What testing do your ingredients go through (specifically titanium dioxide, iron oxides, zinc oxides, and mica)? Are your products comedogenic? Are both grades anatas and rutil structures of Titanium Dioxide safe for use in cosmetics?