Bentonite clay
Bentonite is a clay made mostly of the mineral montmorillonite, formed from weathered volcanic ash. It is mined from open pits, dried, crushed and milled, and higher grades are purified by washing out sand and other minerals. Sodium bentonite swells strongly in water to form a gel, while calcium bentonite swells less. Cosmetic brands buy fine powder for masks and powders, and purified grades to suspend particles and thicken water-based products.
Suppliers sell different products under the same name. Specify the one you need.
High-swelling clay that forms thick gels at low use levels; the usual choice for suspending and thickening.
Lower-swelling clay with a softer texture, often sold for masks and powders.
Washed and refined clay tested to the compendial monograph, with tighter limits on grit and metals.
Milled clay sold by particle size, such as 200 or 325 mesh; finer powders feel smoother in masks.
Bentonite reacted with quaternary ammonium compounds (such as quaternium-18 bentonite or stearalkonium bentonite) to thicken oils; these are separate ingredients with their own INCI names.
Compare each result with your own specification when the lot arrives.
Keep bentonite sealed in a dry place; it absorbs moisture readily and cakes once it does. Use dust control when handling fine powder. Shelf life follows the supplier's specification, with a retest of microbiology and moisture for older stock.
Metals, swelling and color vary with the deposit and even within one mine, so read the metals results on every lot and record the mine or origin. Keep a retained sample, and approve color-sensitive products such as masks against a reference sample.
Facts from regulators and standards bodies, each linked to its source.
21 CFR 184.1155 describes bentonite as principally a colloidal hydrated aluminum silicate and affirms it as generally recognized as safe (GRAS) as a direct human food ingredient, used as a processing aid.
Source: ecfr.gov (opens in a new tab)Health Canada's Natural Health Products Ingredients Database states that bentonite is a known source of significant quantities of lead and arsenic, and that heavy-metal testing of finished products must use the total acid digestion test.
Source: webprod.hc-sc.gc.ca (opens in a new tab)The same database entry lists the non-medicinal purposes absorbent, bulking agent, emulsion stabilizer, stabilizing agent and aqueous viscosity increasing agent.
Source: webprod.hc-sc.gc.ca (opens in a new tab)7 CFR 205.605(a) lists bentonite among nonsynthetic substances allowed as ingredients in or on processed products labeled organic.
Source: ecfr.gov (opens in a new tab)This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Manufacturers and distributors whose own websites say they sell it.
Distributor · Oxford, CT
Connecticut supplier, trading as Praan Naturals, of certified organic and conventional carrier oils, butters, waxes, clays and botanicals for personal care manufacturers.
Suppliers are in alphabetical order and none pays to appear. Each claim is checked against the supplier’s own website on the date shown. Ask for the specification sheet and a recent COA before you order, and confirm details with the supplier.
Common forms include sodium bentonite, calcium bentonite, nF / purified grade, cosmetic powder by mesh and organoclays. Ask each supplier for the specification sheet of the exact grade they quote.
Expect identity, swelling power and gel formation, pH, loss on drying and fineness, heavy metals and microbiology, each with its method, specification and result for that lot.
Keep bentonite sealed in a dry place; it absorbs moisture readily and cakes once it does. Use dust control when handling fine powder. Shelf life follows the supplier's specification, with a retest of microbiology and moisture for older stock.
21 CFR 184.1155 describes bentonite as principally a colloidal hydrated aluminum silicate and affirms it as generally recognized as safe (GRAS) as a direct human food ingredient, used as a processing aid. Health Canada's Natural Health Products Ingredients Database states that bentonite is a known source of significant quantities of lead and arsenic, and that heavy-metal testing of finished products must use the total acid digestion test. The same database entry lists the non-medicinal purposes absorbent, bulking agent, emulsion stabilizer, stabilizing agent and aqueous viscosity increasing agent. 7 CFR 205.605(a) lists bentonite among nonsynthetic substances allowed as ingredients in or on processed products labeled organic.
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