Kaolin is a soft white clay composed largely of the mineral kaolinite, formed by the weathering of feldspar rock. It takes its name from Gaoling in Jiangxi province, where it was mined for porcelain.
How it works
Purely physically. Kaolin particles have a large surface area relative to their size, and oil adheres to that surface. As a masque dries, sebum and surface debris are absorbed into the clay and removed when it is rinsed away.
There is no chemical action and nothing is being drawn out of the skin in the sense marketing sometimes implies. Kaolin absorbs what is already on the surface.
The mildest of the cosmetic clays
Kaolin has a lower absorbency than bentonite or French green clay, and a nearly neutral charge. That makes it the gentlest option, and it is why kaolin appears in products for sensitive and dry skin where a stronger clay would be too drying.
Its fine, soft particle structure also gives it a smooth feel, which is why it appears in powders and foundations as well as masques.
Colour and grade
Kaolin occurs in white, pink, yellow and red varieties, with the colour reflecting iron and other mineral content. White kaolin is the most common in cosmetics and the mildest.
Cosmetic-grade kaolin is purified and tested to limits on heavy metals such as lead and arsenic, which occur naturally in clay deposits. This is one reason cosmetic-grade material differs meaningfully from raw clay.
What to expect
The effect is real, immediate and temporary. Absorbing surface oil reduces shine and makes pores look less prominent for a period. It does not change how much oil the skin produces, and it does not alter pore size, which is largely determined by genetics.
