Received an answer from Professor Swoon
Hi Della,
Silica is a thickening agent. it's only added to adjust the thickness or
viscosity. If that's not needed, then there's no purpose for adding the
ingredient. in products with white pigment, silica is also added to prevent
settling of the pigments. It works in the same way, by thickening the product
and making it more difficult for the pigment to settle.
I hope that answers your question.
Doug
So yay, I was on the right lines
Can't wait to meet him although I may just faint or fall on my knees in worship
