100 nm is generally considered the upper limit for nanoparticles so our zinc oxide would NOT be considered a nanoparticle
Science overwhelmingly shows that particles of zinc oxide greater than 30nm, when applied to the skin, do not get absorbed into the body, do not enter the bloodstream, and are not a threat to human health
Color: White or yellowish
Synonyms: Calamine, Zinc White, Zincite, Chinese White Powder
Uses: Zinc Oxide is used in cosmetics and as a pigment, a bulking agent or filler and an opacifier. It is also used in bath soaps, nail products, foot powders and baby lotions. Zinc oxide is an anti-oxidant and is able to soothe, protect and help heal skin. It is also believed to help support an increased amount of cell division and collagen turnover. It is also used in such skin care products as skin lotions and sunscreen lotion. It is used in sunscreen lotion because it is able to absorb both UVA and UVB ultraviolet light and is a physical UV blocker being capable of scattering solar radiation and is excellent for those who are sensitive to the sun. Zinc Oxide can be used as a mild astringent and an antiseptic. It can help treat and relieve moist, painful or itchy skin conditions. In medicinal or pharmaceutical formulations it is used in hemorrhoid and diaper rash medications, as an ointment for skin protection and burns and in caladryl lotion and calamine lotion.