Nano mineral particulates are extremely small particles which are at risk of being absorbed into your skin and blood stream. Non-nano particulates are larger particles which are too large to enter our pores. More specifically, non-nano particulates means that when they are measured, they are >= 100 nM. Unfortunately, this is NOT a regulated claim. Fortunately for Amavara, our chemist and co-founder can substantiate that our Zinc Oxide particulates average a measurement above the 100nM qualification, while still providing the aesthetics of sunscreens that use non-nano particulates.