The disclosure provides a treated inorganic particle, in particular a titanium dioxide particle, having reduced photoactivity, lower acid solubility and improved anti-microbial properties comprising: an inorganic core particle, in particular a titanium dioxide particle; a first treatment of silica, wherein the silica is added in a single step; and a second treatment comprising co-precipitated zinc oxide and alumina. These particles have reduced photoactivity, lower acid solubility and improved anti-microbial properties.