Originally Posted by cherish 66 /img/forum/go_quote.gif Nano? My goodness, I never thought I'd need a chem. degree to swoosh some makeup on my face but, I'm so grateful for the posters that have the advantage of knowing more of the chemical properties. Now what do we (or I in case I'm the only one in the dark!) need to know about nanos? Nano's and micro's are measurements which should properly be nanometers and micrometers if I'm getting it right. So you could have a meter and a kilometer is 1000 meters. A micrometer is 10^-6 meters which means there are 1,000,000 micrometers in a meter, really small. Now a nanometer is 10^-9 meters so there are 1,000,000,000 nanometers in a meter, much much smaller. I don't really have any knowledge regarding it's harmful effects but apparently it's not good to have makeup with particles that are that small. In conclusion nano's are a thousand times smaller than microns. Hope that helped and somebody understood me lol.