Mineral Makeup and Nano Particles
There is no set definition for the term “mineral makeup," so it's important to read makeup labels carefully. Any product that contains minerals as a primary ingredient may be touted as such, but may contain some unhealthy chemicals.
There is some concern regarding the size of the particles in mineral cosmetics and sunscreens. Some powders are made up of micron-sized particles (one one-millionth of a meter) that may be inhaled during application. Other mineral makeups contain nano-sized particles (one one-billionth of a meter) which recent research shows may cause a health risk. One such study has shown that titanium particles ranging from 826 nanometers to 2368 nanometers might enter the brain, causing oxidative stress. While it is unlikely that these small particles are able to pass the skin barrier, they are also able to penetrate deep in the lungs.
Most mineral makeup companies have kept their particle size larger in order to retain their light reflecting properties, as the smaller the particle, the smoother the effect on skin.
There is still the issue around breathing in the micron-sized particles on a daily basis, and we recommend keeping this in mind when in contact with the powders.
Here is a breakdown of the particle sizes for your reference. Adding a binder and/or pressing your powders will also help keep particles from becoming airborne.
Oxides and Lakes: Generally over 100 microns.
Micas: 10-150 microns (anything over 150 microns is not approved by the FDA for cosmetic use on the face).
Ultra-fine Mica: 5-25 microns
Micronized Zinc and Titanium: Less than 10 microns