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. A micrometer, also known as a micron, is 1000 times smaller than a millimeter.
1 millimeter (mm) = 1000 micrometers (μm)
25,400 micrometers = 1 inch
Chemical Weathering of Clay
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.
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
the presence of organic matter and active enzyme
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.
Below is a brief description of a few 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