Silica is a mineral found all over the planet -- in sandstone, clay, granite, even in plants and animals! It is the main ingredient in glass.
Particle size (2-15 microns).
We would suggest experimenting with Silica at 1% - 15% by weight of the formula for a powdered product.
If you haven't tried working with silica in your formulary yet, we encourage you to sample some. It really improves the performance and feel of the product and it is a very natural addition to the ingredients list.