French Green Clay
French green clay is a substance that is used for external cosmetic treatments as well as some internal applications by practitioners of alternative medicine. It was used in ancient Egypt, Greece, and Rome to treat a variety of skin problems and digestive disorders.
From the standpoint of mineralogy, French green clay belongs to a subcategory of clay minerals known as illite clays, the other two major groups being kaolinite and smectite clays. Clay minerals in general are important because they make up about 40 percent of such common rocks as shale, and they are the main components of soil. Illite clays are usually formed by weathering or by changes produced in aluminum-rich minerals by heat and acidic ground water. They often occur intermixed with kaolinite clays—which are typically used in the ceramics industry. Illite clays have been used successfully by environmental managers to remove such heavy metals as lead, cadmium, and chromium from industrial wastewater.
French green clay takes its name from the fact that rock quarries located in southern France enjoyed a virtual monopoly on its production until similar deposits of illite clays were identified in China, Montana, and Wyoming. The clay's green color comes from a combination of iron oxides and decomposed plant matter, mostly kelp seaweed and other algae. Grey-green clays are considered less valuable than those with a brighter color. The other components of French green clay include a mineral known as montmorillonite, as well as dolomite, magnesium, calcium, potassium, manganese, phosphorus, zinc, aluminum, silicon, copper, selenium, and cobalt.
French green clay is prepared for the commercial market by a process of sun-drying and crushing. After the clay has been mined, it is spread in the sun to remove excess water. It is then ground by large hydraulic crushers and micronized, or finely pulverized. The last stage in the process is a final period of sun-drying to remove the last traces of water. French green clay is available in a dry powdered form for a variety of uses as well as in premixed soaps, scrubs, facial powders, and masks for cosmetic purposes. Prices for an eight-ounce jar of powdered clay range between $4.50 and $11.00 in health food stores. Soaps made with French green clay are priced at about $4.50 a bar.
As a rule, French green clay masks should be used only once a week because the clay tends to dry the skin. In addition, cosmetics containing French green clay are not recommended for naturally dry or sensitive skins, as the mineral content of the clay is an irritant. Soaps made with French green clay should be used only for oily skin.
French green clay may cause constipation when taken internally. Some practitioners recommend drinking only the water without the clay at the bottom of the glass in the morning for this reason.
Alternative healers state that French green clay should never be mixed with metal spoons or stored in metal containers; the only materials that should be used in preparation or storage are wooden spoons or glass stirrers, and either glass or ceramic containers. It is thought that the clay loses its beneficial qualities through contact with metal. This belief has some scientific basis in the fact that illite clays have been found to be highly effective in removing heavy metals in the wastewater produced by various industries.
French green clay may cause skin rashes or patches of dry flaky skin when used on the face. It may cause constipation when taken internally. No side effects from mineral baths or poultices have been reported.
A group of American toxicologists reported in 2003 that illite clays as a group appear to be safe for short-term internal use in humans as well as external cosmetic applications. There have, however, been isolated reports of lung damage caused in workers exposed to particles of montmorillonite—one of the major components of French green clay—in spray paints and primers.
No interactions with prescription drugs or herbal remedies have been reported for French green clay as of 2004. However, because of the adsorptive qualities of French green clay, it may interfere with absorption of medications.
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Cosmetic Ingredient Review (CIR). 1101 17th Street NW, Suite 310, Washington, DC 20036. (202) 331-0651. Fax: (202) 331-0088. <http://www.cir-safety.org>.
Society of Cosmetic Chemists (SCC). 120 Wall Street, Suite 2400, New York, NY 10005-4088. (212) 668-1500. Fax: (202) 668-1504. <http://www.scconline.org>.
U. S. Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857-0001. (888) INFO-FDA. <http://www.fda.gov>.
Rebecca J. Frey, PhD