ILIA Mascara is 100% natural although we have to say ethylhexylglycerin, a preservative, is a bit grey area. This because even though it is naturally derived, it has gone through some processes so you can maybe not really call it natural anymore.
However with mascara's it's very important that they are preserved well, because the product comes near the eyes. We don't see this ingredient as a problem, because the ingredients of ILIA's mascara's are simply very good. And it's virtually impossible to make a 100% natural mascara without preservatives, unless alcohol is used, which we are not a fan of either.
More info about our natural mascara's can be found here: http://amazingy.com/en/natural-mineral-organic-makeup/clean-mascara/