Recently, I had a Mom from Florida call to order our mineral makeup kit for her daughter. The daughter wanted to explain the making of cosmetics in a science exhibit for her school. Brilliant!
In addition to selling them the kit, I immediately directed them to this very excellent, non-commerical website about pigments, Pigments Through The Ages: http://webexhibits.org/pigments/
This site has lots of pretty pictures and easy-to-read historical info about pigments but it also drills down into fascinatnig details on chemical structure and manufacture.
The sister sites include Causes of Color and Color http://webexhibits.org/causesofcolor/, Vision and Art http://webexhibits.org/colorart/, both wonderful sites for your budding scientist/artist.