Clay, when used as part of a skincare product, is a powerful ingredient. Clay itself is simply a refined kind of dirt, literally dug up from the ground and purified for use on the skin. The purification is important, of course; it removes toxic heavy metals, chemical contaminants, and other ingredients from the clay, so you’re left with only the good stuff.
You can’t just go out and get "clay" to use on your skin, though. If you try, you’ll quickly realize there are dozens of different kinds of clay between different brands, different colors, and different formulations. What’s the difference? What’s the low down? Well, good news; we’re here to dish out the dirt on clay.
Types of Clay
First, let’s talk about the different types of clay. Clay types reflect two things: their location of origin and their chemical composition. While we said clays were purified up above, and that’s true, they’re only partially purified. Toxins and contaminants are removed, but natural minerals are not.
You’ll often find that a single type of clay has several different names, so we’re going to try to be as broad as possible and list many of them.
Clays labeled by their color, by the way, can be several different kinds of clay. For example, a "green clay" could be any clay that is simply tinted green but is really a more common clay like illite clay.
All clays are "hydrous aluminum phyllosilicates", and the primary differentiation between them is the minerals that run through them. Different predominant minerals mean different "kinds" of clay with slightly different mineral properties.
Kaolin Clay – This kind of clay is one of the most common kinds of clay you’ll find as part of skin treatments. The origin of the name comes from Chinese, so it is also known as China Clay. In pure form, it’s white, but different mineral impurities can give it different colors, including red, blue, brown, pink, and yellow. Many Brazilian colored clays are Kaolin clays under a different name. Kaolin clays are also produced as part of industrial processes and aren’t necessarily organic.
Smectite Clay – Clays in the Smectite group are found all over the world, and even out of this world! The Curiosity Rover actually confirmed the presence of smectite clay on the planet Mars. Like Kaolin Clay, Smectite Clay is white in its purest form, but it’s rarely found pure. The most common form of Smectite Clay is Montmorillonite Clay, also known as French Green Clay or Sea Clay. Yes, the two are very similar, though Sea Clay is often harvested from sea beds, while French Green Clay is harvested from other areas of France.
Illite Clay – Illite Clay was first identified in the Illinois region of the USA in 1937. It rests chemically somewhere between Kaolin Clay and Smectite Clay in terms of cation-exchange capacity, and it usually has other minerals such as chromium in it.
Bentonite Clay – Bentonite clay comes in several forms, based on the mineral that makes up the dominant chemical formula. The most common versions are sodium bentonite, which is used in oil and gas drilling; calcium bentonite, which is used in oil absorption and cleanup; and potassium bentonite, which is primarily made of volcanic ash and is one of the more common skincare clays.
Fuller’s Earth Clay – Fuller’s Earth clay is a type of clay that has been in use for centuries as a purification and decolorization agent. It’s very, very good at absorbing oils and pigments, and is used in everything from cat litter to absorbing oil from oil spills. It is also, of course, used as a skin treatment, and can even have a skin lightening effect. However, it’s interesting to note that Fuller’s Earth is actually mostly just Calcium Bentonite.
Rhassoul Clay – Rhassoul Clay comes from a particular area in Morocco and is a vibrant red clay, given its color primarily by magnesium. It’s a type of Stevensite, which is itself part of the Smectite Group of clays.
So, to draw things back to the original topic of colored clays:
- Pink clay is generally going to be a type of Kaolin Clay, given its color through minerals like magnesium and iron. Kaolin clay can come in a variety of colors.
- Green clay is most often going to be Montmorillonite (French Green) or Sea Clay, but can also be Kaolin clay, so paying attention to the origin is important.
- White clay can be virtually any type of "pure" clay, as the minerals that form most clays are white in their purest form. Usually it’s Bentonite clay, though.
If all this talk about minerals and clay composition and impurities interests you, feel free to do some research on your own. Mineralogy is a broad and fascinating topic with tons of depth, both figuratively and literally.
The Benefits of Clay for Skincare
Clay is most often used as part of a face mask, but it can be found in smaller proportions in exfoliating scrubs, lotions, and a wide range of other products. The biggest benefits you get from it, though, are by far from face mask applications. So what are those benefits?
Clay is absorbent, particularly of oil. In fact, one of the biggest global uses of clay is in various forms of absorbent media. It’s used in cat litter, it’s used to clean up oil spills, it’s used to remove oil stains from clothing, and so on. In some ways, it’s even more absorbent than activated charcoal, at least when it comes to oil.
On your skin, clay masks can help absorb the oil that covers your skin, and the sebum that fills your pores. When you leave the clay to sit as a mask for a while, and then remove it, it takes the oil with it and leaves your skin feeling clean and fresh. It’s generally best to follow up a mask with some kind of moisturizing and protective lotion to keep it clean afterward.
Clay can help exfoliate, removing dead skin and clearing pores. In addition to the benefits of exfoliation itself, removing the crud on your skin can also help with acne and breakouts. Clay masks are usually gentle enough to help remove dead skin, oil, and contaminants without causing undue irritation of the skin beneath it.
This can help reduce redness and irritation, as well as inflammation caused by impurities stuck to the skin. A regular routine of a clay mask, a gentle cleansing lotion, and a protective medicated cream can go a long way towards reducing the duration and intensity of acne flare-ups.
Some clays may have a complexion brightening effect. One of the effects of clay on substances is decolorizing them. In other words, in some circumstances, clay can act similarly to a bleach, removing the color from a substance.
Will clay bleach your skin? No. The color of your skin comes largely from the melanin found in every cell. That melanin in both parts of your genetic and is much deeper in your skin than the clay can reach.
What clay can do is help remove surface-level impurities and damage, such as the effects of sun exposure over time, or staining from external causes. You may end up slightly lighter in complexion, but it won’t be a dramatic effect.
Clays can be soothing for poison ivy rashes. Studies have shown that the application of a clay mask can soothe rashes caused by surface-level irritants like poison ivy. The chemicals in poison ivy that causes rashes are oil-based and can be partially lifted away from the skin by a clay layer. Additionally, the clay itself helps to soothe the skin and helps prevent you from scratching it, which further damages it and makes the rash worse.
Clay will not cure a poison ivy rash, but it will lessen its duration and intensity. The sooner you can apply it, the better, as well.
Clays can have some appetite suppressant and weight loss benefits when ingested. The majority of this article focuses on the benefits of clay when used as a skin treatment or mask, but what about eating it? Yes, clay is just dirt, a purified mineral. However, clay supplements are not unheard of. Can you see benefits from eating clay?
The answer is, potentially yes. Clay is not a food, for one thing, but it is filling. When you eat clay, your body goes through the motions of trying to digest it, but it can’t. You may absorb some trace minerals, but for the most part, it will simply pass through you. While it’s in you, though, it will slow down your digestive system, which makes you feel full for longer and reduces your desire to eat.
Clay might have benefits as a sun protection ingredient. The FDA does not approve clay as a sun-resistant ingredient, and indeed, a small amount of clay won’t make a difference. Something on the order of a clay mask, however, physically blocks a lot of the sunlight from reaching your skin. It’s not ideal for a full-body covering and it won’t work on the beach if you intend to go in the water, but for a little sunbathing in the back yard, it can be fine as a protective coating.
Does Color Impact the Benefits of Clay?
Yes and no. The color of the clay itself doesn’t really matter, because different kinds of clay can be the same color because of the minerals in the clay. What matters is the primary components of the clay. 
In general, the brighter the color of the clay, the softer and gentler its effects will be, because the concentration of non-clay minerals is higher. Red clays tend to be the softest, while white clays are some of the harshest.
Really, though, clays can have a wide variety of different formulas, so you’re best off looking at the ingredients and doing your research. Some bright and vibrant clay masks are colored because of additives that aren’t originally in the clay. Some might not even have the mineral that would normally give it that color. Always make sure you’re getting what you want to be getting, not something that’s just attractive because of the bright color or the name.
Cautions Regarding Clay
One of the biggest things to watch out for with clay is false claims about what it can do. For example, one of the biggest "benefits" of clay is that it detoxifies the body. That’s fine, but have you ever looked at the studies cited to prove that effect? We have. You’ll almost always see studies like this one that, yes, prove that clay can absorb toxins ingested… when it is also ingested.
In other words, clay only detoxifies your body when you eat it. It doesn’t have any similar effects when applied to the skin; indeed, how could it? It’s not leeching into your bloodstream through your skin, your skin is a barrier explicitly designed to prevent that from happening.
As far as safety, clay won’t really harm you in any way unless it has some kind of toxic or caustic impurity in it. Buying cosmetic-grade clay means it will have such impurities removed, so it should be entirely safe to use.
The only real caution is that clay universally has a drying effect on the skin, though the degree to which it dries out your skin will vary from clay to clay. If you typically have very dry skin, you should avoid using all but the most gentle of clay masks.
