Oxides we use fall into the Pigment category.
Pigments, like most colorants out there, do not fall into the natural category. But take heart, they are “nature identical.”
Pigments are manufactured in labs and have been since the 70′s. Apparently, pigments (oxides and ultramarines) used to be mined but the FDA stepped in and demanded some purity, so since then, these colorants have been manufactured in a lab – same molecular structure just a different way of processing.
Some Iron Oxides are still extracted naturally; however, Iron oxides in nature (dirt) are often stuck with toxic metals like lead, arsenic, mercury, antimony and selenium (when they are in nature). This is why the FDA stepped in to regulate cosmetic colorants so the level of toxic metal present are present in such low concentrations that they are considered “safe.” In fact, only synthetically prepared iron oxides are approved for use in cosmetics in this country. (Johnson, S.T. & Wordell, C.J. “Homeopathic and herbal medicine: Considerations for formulary evaluation,” Formulary, 32, 1167, Nov. 1997. )
The following information is from an article posted in Teach Soap Blog.2012
We offer some products with pigments based on the demands of a portion of our customers who do not have any skin related sensitivities or reactions. They enjoy the unique colors knowing they are approved as safe to use. Please refer to the individual bar description for color specifics.