Kaolin, Pink, Green and Bentonite: Cosmetic Clays Compared
Cosmetic clays differ mainly in how much oil and water they absorb. Here is how the common ones compare, which is gentlest, and which suits which skin.
Kaolin is the gentlest cosmetic clay because it barely swells and absorbs the least. Pink clay is usually kaolin coloured with iron-rich red clay and is almost as mild. Green clay is more absorbent, and bentonite absorbs the most because it swells strongly in water.
Clay shows up in soaps, masks and cleansers, usually with a colour in the name and a promise attached. The colour is the least important thing about it. What separates one clay from another is how much it absorbs, and that decides who it suits.
The one property that matters
Clays are made of very fine mineral particles, arranged in layers. Some clays let water slip between those layers and swell up. Some barely swell at all. A clay that swells strongly can take on a lot of water and oil, so it feels more drawing on skin. A clay that hardly swells is gentle.
That single property explains most of the differences people notice.
The common clays, gentlest first
| Clay | What it is | How absorbent | Best suited to |
|---|---|---|---|
| Kaolin (white) | Mostly the mineral kaolinite | Low | Dry, sensitive and reactive skin |
| Pink | Usually kaolin blended with an iron-rich red clay | Low | Sensitive skin that still wants a little clarity |
| Green | A more absorbent mineral clay, coloured by its mineral content | Medium | Normal to oily skin |
| Bentonite | Mostly montmorillonite, a strongly swelling clay | High | Oily skin, and masks rather than daily use |
Kaolin
Kaolin is mostly the mineral kaolinite, which has a low shrink-swell capacity. It takes on little water and draws only lightly on skin. That makes it the gentlest of the group and the safest starting point if your skin reacts to almost everything. It also gives a soap a silky slip.
Pink clay
Pink clay is usually not a single mineral. It is generally kaolin mixed with a red clay, and the colour comes from iron oxides. Because it is mostly kaolin, it behaves much like kaolin: mild and low in absorption. It is a good choice when you want something marginally more clarifying than pure white kaolin without moving to a strong clay.
Green clay
Green clays absorb noticeably more than kaolin. They suit normal and oily skin, and they can feel too drying for skin that is already dry, particularly in a leave-on mask.
Bentonite
Bentonite is mostly montmorillonite, a clay that swells strongly in water. That makes it the most absorbent of the four. It is very effective on oily skin and in masks, and it is the one most likely to leave dry skin tight. In soap it is used in small amounts, often as much for the slip it gives the lather as for anything it does on skin.
How to choose
- Your skin reacts to most products: start with kaolin or pink.
- Normal skin, no strong preferences: any of them in a bar will be fine. Pick on look and feel.
- Oily skin, or you like a very clean feel: green or bentonite.
The short version
The colour of a clay is mostly a clue to its minerals. What matters is absorbency. Kaolin and pink are the gentle ones, green sits in the middle, and bentonite absorbs the most. Match the clay to how much oil your skin actually has.
Sources
- secondaryWikipedia: KaoliniteKaolinite has a low shrink-swell capacity and a low cation-exchange capacity, which is why it is the mildest of the cosmetic clays.
- secondaryWikipedia: BentoniteBentonite as an absorbent swelling clay made mostly of montmorillonite.
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