Incorporating Gold Mica in Water-in-Oil Sunscreen/BB Cream

You're experiencing a common challenge when adding mica to water-in-oil (W/O) emulsions, especially those containing white pigments like Titanium Dioxide or Zinc Oxide. In a water-in-oil system, water droplets are dispersed within a continuous oil phase. Mica powder, being typically water-dispersible, tends to get trapped within these internal water droplets.

Sunscreen pigments like Titanium Dioxide and Zinc Oxide, particularly those treated for use in oil-based or W/O formulas, are dispersed in the external oil phase. When you apply the product, the oil phase (containing the white sunscreen pigments) is what coats the skin, effectively covering the water droplets and the gold mica trapped inside them. This is why the gold color appears faint or invisible.

To make the gold mica visible and achieve the desired shimmering effect, you need to ensure the mica is dispersed in the oil phase of your formulation, alongside the sunscreen pigments.

Here's how to approach it:

1. Add Mica to the Oil Phase: Instead of adding the gold mica powder to the water phase, incorporate it directly into the oil phase. Mica powders like Bright Gold Mica are dispersible in oils and silicones.
2. Ensure Proper Dispersion: Before combining the oil and water phases for emulsification (using emulsifiers like Water-in-Oil EZ™ or Water-in-Oil Max™), make sure the gold mica is thoroughly dispersed in the oil phase. You may need to mix or mill the oil phase containing the mica and sunscreen pigments to achieve a uniform dispersion.
3. Consider Mica Particle Size: The particle size of the mica affects the shimmer intensity. Larger particle sizes (like Size B or D) generally provide more noticeable sparkle than smaller ones (Size A).

By dispersing the gold mica in the oil phase, it will be present on the surface of the emulsion droplets and come into direct contact with the skin upon application, allowing its golden shimmer to be visible alongside the sunscreen's white base. While the white pigments may still slightly influence the final appearance, this method will significantly improve the visibility of the gold color compared to adding it to the water phase.