Our Earth is made up largely of minerals and so is clay. It should not be surprising to find out that the use of clay as medicine traces back to the dawn of civilization. Even animals instinctively use mud to ward off insects and bugs, protect themselves from excessive sun and to generally heal and protect their skin.
Clays and clay minerals have been mined since the Stone Age and have been used in beauty care for hundreds of years. Clays were used by Native Americans as a natural way to purify, soothe, and heal skin and wounds.
Clays have the ability to exfoliate, absorb excess oils, cleanse dirt and impurities and invigorate the skin.
Regular use of pure cosmetic clays can remove dead skin cells, remove debris and impurities from the pores, improve circulation and bring about a smooth healthy glow to the skin. When combined with water, clays can bind to impurities and eliminate them from the skin and hair.
What is Clay?
Clays are a soft, loose, earthy material mainly found in mineral clay deposits that lay on or just below the surface of the Earth. Clays have a very small particle size which is usually less than 2 micrometers in size.
Clays are made of minerals and form over long periods of time as a result of the gradual chemical weathering of rocks.
Chemical weathering is the decomposition of rocks due to chemical reactions that occur between the minerals in the rocks and water, acids and oxidation from environmental conditions. Most clay minerals are formed where rocks are in contact or were once in contact with water and air.
Water: Water is the main agent of chemical weathering. Feldspar, one of the most abundant rock-forming minerals, chemically reacts with the many chemical compounds found in water to form clay.
Acid: Water contains many weak acids such as carbonic acid which forms when carbon dioxide in the air mixes with rainwater. Sulfur dioxide and nitrogen gases also create acid rains that act as chemical weathering agents.
Oxidation occurs when oxygen combines with other substance present in the rocks and creates compounds called oxides. Rust, for example, is iron oxide. When rocks are exposed to air and water, these oxides undergo oxidation, which weakens the rocks and causes them to break apart. Source: www.americangeosciences.or
Natural clays can come in many colors.
While color is often used to identify and differentiate clays, it is not very accurate. Illite, montmorillonite and kaolin clays all come in a variety of natural colors, but it is the structure of the individual clay minerals that makes them effective in differing ways.
The rainbow of clay colors available reflects the variety of unique minerals contained within the clay. Green and blue from ions of ferrous and magnesium as well as decomposed organic material. Yellow clays are rich in from ferric oxides and red clay color comes from ferrous and copper oxides. White clay is high in aluminum.
The mineral content is affected by . . .
- the soil composition of the area from which the clay was mined
- where and how deeply the clay was mined
- the type rocks from which it was derived
- chemical weathering
- the presence of organic matter and active enzymes
Buyer beware: Be sure that you are purchasing clay from a reputable source. Unfortunately, the increasing popularity of cosmetic clay has led to the creation of many very colorful "clay" products that are either not clays at all or are clays that are blended with natural or synthetic colorants.
Cosmetic Clays in Skin Care
Clays are classified by their unique mineral content and their crystalline structure. Their mineral content and physical structure, like color, depends on the place from which the clay is mined.
There are many different clays available for cosmetic use and due to their unique chemical makeup, each type of clay exhibits different properties and thus provides a different benefit to the skin.
Clays are usually a mixture of a variety of minerals with one or two minerals being predominant. Based on their mineralogical makeup there are three main types of clay families used for cosmetic purposes, Kaolinite, Illite, and Smectite (Montmorillonite).
Understand that there is no such thing as a "pure one mineral clay" found in nature. While clays are classified based on their major mineral components, all clays contain natural trace minerals that will differ depending on the areas from which they are mined. For example, Bentonite clay may contain a high percentage of Montmorillonite, Illite or Kaolin clays. Unfortunately, this leads to a lot of confusion in naming.
The Very Simple Science of Clay
The study of clay is a complex subject that soil chemists and other scientists dedicate their lives to research and understanding.
While there is a great deal of anecdotal information about the benefits of clay as well as descriptions of the types of cosmetic clay, there is little information and no scientific studies concerning exactly how clay works for the skin. I do believe that the "science" of clay, based on soil chemistry, may help explain.
There are two basic factors that affect how a certain clay works to cleanse and detoxify skin, its Cation-Exchange Capacity (CEC) and sorptive properties. Here is a very simple explanation:
Cation Exchange Capacity
The measure of the cation exchange capacity is mainly used in soil chemistry to study the ability of soil particles (part of which are clay) to hold and release plant nutrients. Clay and soil particles have a negative charge but when mixed with water the surface of this wet clay now has a positive charge due to its cation exchange capacity (CEC). This concept is extremely important in agriculture since it is a key determinant of soil fertility. But it can also explain how clay can interact with skin.
Cation Exchange Capacity, abbreviated CEC, measures the number of cations (positively charged ions) that can be retained on the negative surface of the clay and then can be exchanged with other positive ions (cations) when dissolved in a water-based solution.
Remember that opposites attract, so in order for the positively charged cations to bind to the surface, the clay needs to have a negative charge, to begin with. The higher the CEC, the higher the negative charge of the clay and the more cations it can hold. The CEC actually quantifies the ability of a clay to release cations.
For example, when mixed with water the negatively charged particles on the clay's surface become bound to the positively-charged minerals in the water. The theory is that since clay is made largely of minerals, these positively charged good minerals are then able to exchange with positively charged impurities in the surrounding area which are removed from your face as part of the clay, thus leaving good natural minerals behind on your skin.
While clays can be used as a dry powder, the properties of clays described become activated by water. This activation occurs when water is absorbed into the clay and the clay can then take on and release cations. (That is why the cation exchange capacity is important)
Sorptive properties describe the process by which one substance becomes attached to another.
For example, does the clay absorb other substances like a sponge, or does the clay adsorb which means it holds the substance on its surface like a magnet?
Natural cosmetic clays and their uses for skincare
While all cosmetic clays have the ability to draw oil and impurities from the skin, some have stronger drawing abilities than others. Thus, based on your unique skin type, one clay type may be better for your skin than another. Understanding the benefits, the differences and how they may work for your skin is the first place to begin when choosing a clay. For example:
Kaolin clays are good for dry to normal skin
Bentonite and Rhassoul clays are good for normal, combination or oily skin
Illite clays, like French Green clay, are best for oily skin
Just remember that your skin is unique!
Bentonite is part of the Smectite clay family, which are clays that have a three-layer structure which gives the clay a tremendous ability to swell when water is added.
When mixed with water, bentonite swells up like a sponge and becomes very slippery and almost gel-like.
The ability of clays to swell should not be confused with the ability of the clay to remove impurities.
Bentonite also has a high cation exchange rate. When mixed with a water-based liquid, bentonite produces a negative charge that draws out positively charged impurities.
Bentonite clay, a powerful healing clay, is composed of volcanic ash, with a high percentage of montmorillonite, a group of soft minerals. The presence of iron and magnesium ions give Bentonite Clay a subtle greenish-grey color.
The U.S. is the top producer of bentonite clay. Clays, like Bentonite, are often named after their location. Bentonite was first discovered in the US in 1898 near a city called Fort Benton, located in the Wyoming, Montana region of the United States. According to the Wyoming Mining Association:
The name Bentonite is sometimes used interchangeably with Montmorillonite. However, although they have very similar mineral properties they are not exactly the same.
There are other clays that are composed of a large amount of montmorillonite. These clays are often called Sea Clays, Fuller's Earth, Red Montmorillonite, Green Montmorillonite, and others. There is no real standard for the way in which clays are named which can become very confusing for the consumer.
There are different types of bentonite clay; each one is named after the dominant element in the clay, such as potassium, sodium, calcium, magnesium or aluminum.
Good for all skin types, bentonite it is commonly used in shaving soaps to provide slip, so the razor glides over the skin which helps prevent cuts and razor burn. When used in natural clay deodorants, nutrient-rich bentonite clay helps absorb sweat naturally.
INCI Name: Montmorillonite or Bentonite
Appearance: Fine odorless powder, natural cream/grey colored clay
Texture: Slightly grainy, but feels smooths and soft when pressed between the fingers
Skin Type: Works well on all skin types, but is especially helpful for normal, oily, combination or acne-prone skin
Skin Care Benefits: Bentonite clay is packed with minerals including calcium, magnesium, silica, sodium, copper, iron, and potassium. Bentonite is a very absorbent and adsorbent clay and works well to draw out most skin impurities and excess oils. It is particularly recommended for oily, acne-prone skin, has exfoliating properties, and helps reduce the appearance of pores and blackheads.
- Refreshes skin by removing dead skin
- Has astringent properties which help shrink enlarged pores
- Helps with oily, congested and acne-prone skin types
- Provides gentle exfoliation to help remove excess oils, unclog pores and tighten skin
- Promotes blood circulation to the skin which helps the healing and regeneration process
- Softens skin
- It is often used in shave soaps for the silky slip that it provides
- Helps ease irritations and calm itching caused by cuts, burns, eczema, and psoriasis
- It also draws out the dirt, impurities, and product build-up on the hair and scalp to encourage hair growth.
The primary component in kaolin clay is the mineral kaolinite, a hydrous aluminum silicate formed by the decomposition of minerals such as feldspar.
Kaolins are non-swelling clays and do not absorb like other clays--they adsorb which means they do not soak up impurities like a sponge, but rather hold them on their surface like a magnet.
Kaolin is often used as the clay for china pottery. Its name comes from a Chinese word which means "high ridge." The high ridge is a reference to the hill in south-eastern China where the clay was thought to be originally mined. Although white Kaolin is often called "China Clay," the best deposits are not located in China.
Kaolin, which is mined in the US, France, Germany, England, and the Czech Republic, is one of Georgia State's largest natural resource.
White kaolin clay is also known as "White China Clay," but can be found in a variety of natural colors depending on its combination with other trace minerals.
For example, Kaolin clay can be a pink, red or orange in combination with naturally occurring iron oxide, or a yellowish pink when in combination with feldspar. Pink or rose kaolin can be from naturally occurring iron oxides or sometimes it is a combination of white kaolin mixed with red kaolin.
When added to soap, kaolin imparts a silkiness to the lather, acts as a gentle exfoliant, mild cleanser and can also add natural color.
INCI Name: Kaolin
Appearance: Fine odorless powder
Texture: Very fine, soft, fluffy and lightweight
Skin Type: Works well on all skin types, but is especially good for sensitive skin
General Skin Care Benefits of Kaolin Clays: White clay is the softest and least drying to the skin. It is best for people with dry and sensitive skin and can even be used in all-natural body powders and all-natural baby powder, instead of cornstarch, to prevent diaper rash or chafing.
- It is the mildest of all clays and is suitable for people with sensitive skin
- Helps draw out oils without being harsh on the skin
- Since it does not draw oil like other clays, it is very helpful for people with naturally dry skin
- Stimulate blood circulation to the skin which helps brighten skin
- It has a larger particle size which can provide gentle exfoliation and cleansing
- Softens skin
- Rich in silica, helps clean the scalp without drying. It calms inflammation, helps moisturize and revitalize dry, damaged hair.
Skin Care Benefits of Kaolin clay based on colour:
Kaolin clays can be found in many colors.
Again, the area from which the kaolin is mined will determine its mineral content which in turn determines the color and how it acts on the skin.
Although all of the kaolins are gentle clays that share the properties described above, their properties, especially the ability to draw oil from the skin, vary a bit based on the trace mineral content and thus the color.
White kaolin is considered the mildest and least drawing of the kaolins. As the hues deepen, so does its ability to draw oils and impurities from the skin.
White kaolin: For all skin types. White kaolin clay is the gentlest and thus great for sensitive dry skin. It absorbs less than other clays but softens skin with fine gentle particles that provide mild exfoliation and while preventing the skin from becoming overly dry.
Yellow kaolin: For dry sensitive skin. Yellow kaolin clay is slightly more absorbent and exfoliating and better at stimulating circulation but is still very gentle for sensitive skin.
Red kaolin: For normal to a bit oily skin. Red kaolin clay contains a higher amount of silicate and has the most absorbing powers of all the kaolins. It is rich in natural iron oxides and is a great addition for slightly sensitive but acne-prone skin.
Pink (Rose) kaolin: For combination skin. This clay whether naturally pink or a mixture of white and red kaolins has the properties of both white and red kaolin. This can be the ideal balance for those with sensitive skin that has a bit excess oil and needs gentle exfoliation. It also makes a great natural face powder or blush.
Orange Kaolin: For normal or combination skin. This clay is similar to Pink Kaolin but has a bit more drawing power.
Illite clays are highly absorbent but non-swelling clays.
They have a three-layer structure which gives Illite clays a stronger drying and drawing effect.
Although there are many types of illite clays, the best known is French Green Clay.
The color of French Green Illite Clay comes from a combination of iron oxides and decomposed plant matter, mainly kelp and other algae.
The active minerals in green illite clay include dolomite, magnesium, calcium, potassium, manganese, phosphorus, zinc, aluminum, silicon, copper, selenium, and cobalt as well a small percentage of montmorillonite.
Originally mined from regions in the North of France and the Atlantic basin, French Green Illite is sometimes called marine clay since the quarries were found in ancient marine beds--which gives it a very rich mineral content.
Our French Green clay is quarry mined from naturally occurring deposits in France and is untreated. Although originally mined in France, not all French Green Clay originates in France. Clay deposits are now also mined in Wyoming, Montana, China, and other European countries.
INCI Name: Illite
Appearance: Fine odorless powder with a soft texture and a light green color. When mixed with water its rich green color is revealed.
Texture: Slightly grainy, but feels smooths and soft when pressed between the fingers
Skin Type: From normal to oily skin and scalp
Skin Care Benefits: French green clay is highly absorptive and adsorptive, it acts as a magnet for impurities. It stimulates blood flow to the skin, removes oils and impurities and exfoliates dead skin cells. As the clay dries, it causes the pores to constrict, producing a firmer feeling skin.
- Toning action stimulates the skin by bringing fresh blood to the surface
- Helps with oily, congested and acne-prone skin types
- Helps to remove excess oils, unclog and shrink pores and tighten skin
- Exfoliates dead skin cells
Note: Even those with oily skin should limit the use of French Green Clay to a maximum of one use per week.
There are also other colors of Illite Clay. Just as with the Kaolins, they share similar properties to those described above, described above, especially the ability to draw oil from the skin, but they based on the mineral content and thus the color.
Red Illite clay is similar in properties to other Illite clays, the only difference is its higher concentration of iron oxides.
Yellow Illite is similar to Green Illite in its therapeutic and cosmetic properties and uses. Its soft yellow color is attributed to the presence of natural iron oxide (less than Red Illite). It leaves skin fresh and bright.
Rhassoul, or also known as Ghassoul, gets its name from the Arabic verb "rhassala,” meaning “to wash." The main component of this ancient clay is magnesium silicate.
It is a natural mineral clay extracted from deep deposits inside the Atlas Mountains in Morocco, and unlike many other clays, has not been exposed to surface contaminants
It is part of the Smectite group of clays, like Bentonite, which means it has a tremendous ability to swell when water is added.
The molecular structure of Rhassoul clay gives it a unique ability to absorb excess dirt and oil, as well as extract impurities from the skin. It is extremely rich in trace minerals especially silica, magnesium, potassium and calcium minerals that are beneficial for the skin and has been used for centuries as a cleanser and conditioner for the skin and hair.
Our Rhassoul is untreated and naturally dried with a silky texture. Once extracted, the clay is washed with water to eliminate impurities, then spread out to be sun-dried. The product is then purified and powdered. No solvents or diluents are used in the processing.
INCI Name: Moroccan Lava Clay
Appearance: Very fine, dusty colored, odorless powder
Texture: Silky and soft texture when rubbed between the fingers
Skin Type: Normal and oily skin and scalp; suitable for sensitive skin and skin prone to blackheads
Skin Care Benefits: The high concentration of natural minerals in Rhassoul can help replenish depleted minerals in your skin, resulting in a firmer and more even-toned complexion.
- Helps reduce skin dryness and nourish the skin
- Helps even out skin tone and reduce blemishes
- Helps unclog pores and remove impurities without irritation
- Provides gentle exfoliation to remove dead skin cells to reduce flakiness and improve skin clarity and texture
- Helps to remove excess surface oil
- Stimulates circulation
- Recommended for sensitive scalps, normal to oily hair, and dandruff.
- Although it is great for oily hair, Rhassoul also prevents dryness by nourishing and cleansing the scalp without stripping away the protective sebum.
Clay Buyer's Notes
If you are looking to purchase clays, be sure to buy cosmetic-grade clay that is pure, without additives. Other grades of clay that are intended for crafts or industrial applications are not pure and can contain other components that are not skin-friendly. Cosmetic-Grade Clay has been specially refined and tested for use in personal care products.
Always purchase from a reputable source. Ask questions like . . . how and where is the clay sourced and how is it processed and handled?
Sun-dried clay is the best, as it retains 100% of its trace elements. After natural clay has been mined, it is spread in the sun to remove excess water.
It is then ground by large mechanical crushers to create a finely granulated powder without any chemical additives. The last stage in the process is another period of sun-drying to remove the last traces of water.
Also remember, that the increasing popularity of colored cosmetic clay has led to the creation of many very colorful "clay" products that are either not clays at all or are clays that are blended with natural or synthetic colorants.
Purchase clays in powder form, not those already hydrated. Hydrated clays have added water and therefore need preservatives, which we humans do not need!
ORGANIC NOTE: Naturally occurring clays cannot be "certified organic" by the USDA because the term "organic" is only given to ingredients that are grown or raised under organic supervision. Since naturally occurring clays are neither "grown in a field" nor raised (as with an animal), they cannot be certified organic.
It's All in a Name
The names of clays can be quite confusing. If you are purchasing a clay for its specific skin properties, it is best to check its INCI name. INCI names (International Nomenclature Cosmetic Ingredient) are a uniform, internationally recognized naming system to identify cosmetic ingredients so they are consistently named from product to product.
If you are looking for specific properties in a clay, the INCI name will be the most helpful piece of information. Here are just a few examples of confusing names:
Just like the Scientific botanical names given to plants, the INCI name is for identification only and says nothing about the quality of the ingredient.