A coated powder comprises (a) particles, and (b) a coating on the surface of the particles including (1) silica moieties, (2) organo oxysilane moieties selected from the group consisting of mono-organo oxysilane moieties, bi-organo oxysilane moieties and tri-organo oxysilane moieties, and (3) poly(dialkyl)siloxane moieties. The amount by weight in SiO2 equivalents of the organo oxysilane moieties and the silica moieties is at least 0.0625% of the total coated powder weight per m2/g of the specific surface area of the particle to be coated.