Commercially available cosmetic grade silica is generally spherical silica, most of which are made into 2 to 15
Some μm-sized hollow microbeads have a porous surface, which has good adsorption and lubricity, and absorbs both oil and water. Some silicas are surface-treated with silicone oil, which makes them waterproof and has better compatibility with grease and oil. It is easy to add to W/O’s base makeup formula; due to its high hardness, silica can also give the product excellent pressure resistance.