I frequently hear from new clients about chronic skin reactions they’ve experienced from wearing makeup for most of their lives. It’s deeply unfair that so much important information about ‘natural ingredients’ and ‘natural products’ is kept hidden. These chemicals and micro-plastics don’t just affect our own health—when we wear them around loved ones and pets, they’re exposed too, without any say in the matter. Many so-called natural makeup ingredients—like mica and titanium dioxide—are often coated with chemical additives to change their appearance, boost stability, or improve performance in formulations. But have we stopped to consider the long-term impact on our brains and bodies as we breathe in, absorb, and even ingest these chemical coatings? It’s less of a Trojan horse and more of a chemical masquerade. While we think we’re applying something purely natural, what actually touches our skin isn’t the natural ingredient itself but a particle cloaked in a toxic chemical soup.
Surprising Chemical Coatings
• PFAS Compounds: Even in ‘natural’ or ‘green’ cosmetics, powders like mica can be coated with PFAS (per- and polyfluoroalkyl substances), often for waterproofing or long-lasting properties.
• Aluminum Hydroxide: Used especially on mica, this compound helps create soft-focus powders and is widely incorporated in both natural and conventional makeup.
Effects on Formulations
While the starting ingredients may be naturally derived, the chemical coatings help control color, light reflection, water resistance, stability, and safety but also introduce synthetic elements into otherwise natural-looking ingredient lists. This can be surprising for users seeking truly ‘pure’ natural powders, as these treatments are often not listed in detail on cosmetic labels.
Many consumers are unaware of these coatings, and their presence means that even ‘natural’ makeup products can contain unexpected chemical treatments:
Mica: Mica is frequently coated with barium sulfate or silica to produce fillers with specific textural, reflective, and adhesion properties. Barium sulfate coatings enhance adhesion and application smoothness, while silica coatings improve oil absorption and slip.
Talc: Talc and other flaky minerals like kaolin or sericite are also documented as bases that can receive barium sulfate coatings for better spreadability and adhesion in face powders and other pressed products.
Kaolin & Sericite: These natural clays and minerals act as pigment bases which are often surface-treated with barium sulfate and other chemical compounds for soft focus and adhesion.
Titanium Dioxide: titanium dioxide (often already nano- or micro-sized) is further coated and used as a secondary layer atop treated mica for pearlescent or opacifying effects.
Use of forever chemicals/PFAS/Fluorinated Compounds
Powders—mica, talc, and silicate-based pigments—are sometimes coated with fluorinated compounds, such as perfluoroalkyl phosphoric acid esters, to provide exceptional water and oil repellency as well as long-lasting performance in foundations and eyeshadows.
PFAS-type coatings (including polytetrafluoroethylene/Teflon and other proprietary fluoropolymers) are used mainly to improve water resistance and makeup longevity, often not declared on the ingredient list.
what is the purpose of these coatings?
These coatings are engineered to enhance product feel, longevity, or visual effects, even in cosmetics marketed as ‘natural’. The natural powder ingredients most frequently coated with barium sulfate, silica, or proprietary fluorinated compounds to improve texture, adhesion, or water resistance in long-wear makeup are mica, titanium, dioxide, talc, kaolin clay, and sericite. Mica is particularly common—manufacturers deposit barium sulfate or silica onto mica’s surface to achieve specialized filler and light-reflecting properties. Other flaky mineral pigment bases like talc, kaolin, and sericite are similarly treated with barium sulfate to enhance spreadability, skin adhesion, and masking power. These flakes can then be further coated (such as titanium dioxide) for coloration and performance benefits.
In addition, both mica and titanium dioxide powders are sometimes deliberately coated with fluorinated compounds—including perfluoroalkyl phosphoric acid esters and other PFAS derivatives—to impart water and oil resistance and boost makeup longevity. These coatings are not always explicitly listed on cosmetic labels but are routine in products advertising long-wear or waterproof effects.
what are the most common chemicals used to coat mica?
The most common coating chemicals used on mica, talc, and kaolin in cosmetics are titanium dioxide, iron oxides, barium sulfate, silica, tin oxide, alumina (aluminum oxide or aluminum hydroxide), and proprietary fluorinated compounds (like PFAS types).
• Mica (natural and synthetically made)
• Titanium Dioxide (CI77891): Most frequently used for creating pearlescent or shimmering effects and whitening.
• Petroleum Lake Dyes: Used to colour Mica as natural moskivite mica is transparent to cream to beige to gold and green- that is it.
• Barium Sulfate: Used to enhance adhesion, spreadability, and light reflection.
• Tin Oxide (CI77861): Sometimes used as an additional reflective or functional layer.
• Silica or Aluminum Hydroxide/Alumina: Used to improve moisture resistance, texture, and stability.
• Proprietary Fluorinated Compounds: PFAS is sometimes used to impart water resistance and improved skin adhesion in long-wear products.
Other Common Chemical Coatings
• Magnesium Stearate (processed metal soap)
• Proprietary Fluorinated Compounds (including PFAS types, e.g., polyperfluoromethylisopropyl ether)
• Polymethyl Methacrylate (PMMA) – synthetic polymer coating
• Nylon-12 or polyethylene powders – used as hybrid polymer coatings.
• Methicone (Dimethicone, Trimethylsiloxysilicate) – silicone compounds
Are all these chemicals used to coat mica at the same time?
Not all of these coating chemicals are used on mica, titanium dioxide, or kaolin at the same time; instead, a specific combination is chosen based on desired cosmetic effects, product performance, and regulatory guidelines. Typically, only one or a few of these chemicals are layered or combined in a controlled surface treatment, such as titanium dioxide and barium sulfate for shimmer and adhesion, or silica and alumina for oil absorption and improved feel. Some specialized products may use two or three coatings sequentially, but it is uncommon for all listed chemicals to be present on the same ingredient in a single product. The selection and number of coatings depend on the formulation’s needs and desired visual effect.
Manufacturers will often perform laboratory testing to evaluate how different coatings interact, test for texture, color, performance, and stability, then finalize a coating blend based on these results and the type of product being developed.Coating combinations for mica are selected through a technical process guided by the desired effect (e.g., shimmer, opacity, adhesion), the functional requirements (such as oil absorbency or water resistance), safety regulations, and compatibility with other ingredients. Companies conduct laboratory testing to evaluate how different coatings alter particle properties, working toward optimal texture, color, feel, and longevity for each specific cosmetic product.
And the combination is not required to be listed on the final product’s full ingredient list?
No, the exact combination of coating chemicals applied to mica, talc, or kaolin does not need to be individually listed on cosmetic product ingredient labels. Manufacturers can use umbrella terms or list only the treated pigment’s Color Index (CI) code, without specifying the exact coatings. Full disclosure of proprietary coatings is not standard, meaning consumers and even formulators may not always know all the chemicals used for surface treatment unless voluntarily provided by the supplier or requested for regulatory dossier review.
are nano-sized coatings used?
Yes — natural minerals like mica, titanium dioxide, and kaolin clay are often coated with nano‑sized layers of synthetic compounds in modern cosmetic manufacturing. These nanoscale coatings modify the surface properties of large mineral flakes or particles without making the entire ingredient a nanoparticle itself.
How Nano‑Sized Coatings Are Used:
• Mica: Commonly receives nanometer‑thin films of titanium dioxide, tin oxide, zirconium oxide, or silica using hydrothermal or chemical deposition methods. This creates pearlescent or color‑shifting effects by manipulating light reflection at the nanoscale.
• Talc and Kaolin: These can be treated with nano‑thin silica or alumina coatings to improve texture, oil control, and adhesion, or to make the surface hydrophobic for longer wear.
• Titanium Dioxide (TiO₂): Typically exists as nanoparticles already, but its surface is coated with nanometer‑scale layers of alumina, silica, or siloxanes (dimethicone or methicone) to reduce photocatalytic reactivity and prevent clumping.
Functional Purpose of nano particle coatings
• Improve dispersion and stability
• Enhance optical and reflective properties
• Provide UV protection without whitening
• Increase water or oil resistance
In these formulations, the coating layers are on the nanometer scale (often 5–50 nm thick)
