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Kaolin clay

Kaolin clay suppliers and sourcing guide

Kaolin is a white clay made mostly of the mineral kaolinite, a hydrated aluminum silicate formed by the weathering of feldspar-rich rock. It is mined, mixed into a water slurry, separated from sand and mica, sometimes bleached or magnetically cleaned to remove iron, then dried and milled. It swells very little in water. Cosmetic brands buy fine white kaolin for masks, powders and deodorants, and colored kaolins whose color comes from iron oxides.

Also known as
Kaolin · China clay · White clay · Hydrated aluminum silicate · CAS 1332-58-7
Facts checked
November 2026

Forms and grades of kaolin clay

Suppliers sell different products under the same name. Specify the one you need.

  • White kaolin (USP / cosmetic grade)

    Refined, low-iron kaolin with a bright white color; the standard grade for powders and masks.

  • Colored kaolins

    Pink, red and yellow clays colored by naturally present or added iron oxides; ask whether the color is from the deposit or blended in, since added iron oxides are color additives.

  • Fine and micronized powders

    Milled to a stated particle size or mesh for smooth feel in pressed and loose powders.

  • Low-microbial grades

    Clay heat treated or otherwise processed to a lower microbial count for leave-on and baby products.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Identity
X-ray diffraction or compendial identity tests for kaolinite.
Particle size
Residue on a stated sieve or laser particle size distribution.
pH and loss on ignition
pH of a suspension and loss on drying or ignition against the grade limits.
Color and whiteness
Brightness or color against a reference, which varies with iron content.
Heavy metals
Lead, arsenic, cadmium and mercury by ICP-MS after full acid digestion. Mined clays carry these from the deposit, so this is the test to read most closely on every lot.
Microbiology
Total aerobic count, yeast and mold, and absence of specified organisms such as E. coli, Salmonella, S. aureus and P. aeruginosa. Mined minerals pick up soil organisms, and some suppliers heat treat or otherwise reduce the count; the COA should say which.

Storage, lots and expiry

Storage and shelf life

Store kaolin sealed in a dry place, away from moisture, and handle fine powder with dust control. It is a stable mineral and does not degrade in normal storage. Shelf life follows the supplier's specification, with a retest of microbiology and moisture for older stock.

Lots and expiry dates

Whiteness, particle size and metals vary with the deposit, so record origin, color and metals results for each lot and keep a retained sample. Approve colored clays against a reference sample because shade differs between lots.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • 21 CFR 347.10 lists kaolin at 4 to 20 percent as an active ingredient in the OTC skin protectant monograph.

    Source: ecfr.gov (opens in a new tab)
  • 21 CFR 186.1256 describes clay (kaolin) as hydrated aluminum silicate and affirms it as GRAS as an indirect human food ingredient used in making paper and paperboard that contact food.

    Source: ecfr.gov (opens in a new tab)
  • Health Canada's Natural Health Products Ingredients Database lists kaolin with common names including bolus alba, china clay and hydrated aluminum silicate, and non-medicinal purposes including abrasive, absorbent, anticaking agent and suspending agent.

    Source: webprod.hc-sc.gc.ca (opens in a new tab)
  • 7 CFR 205.605(a) lists kaolin 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.

Kaolin clay suppliers

Manufacturers and distributors whose own websites say they sell it.

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.

Frequently asked questions

What forms of kaolin clay can brands buy?

Common forms include white kaolin (USP / cosmetic grade), colored kaolins, fine and micronized powders and low-microbial grades. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for kaolin clay include?

Expect identity, particle size, pH and loss on ignition, color and whiteness, heavy metals and microbiology, each with its method, specification and result for that lot.

How should kaolin clay be stored?

Store kaolin sealed in a dry place, away from moisture, and handle fine powder with dust control. It is a stable mineral and does not degrade in normal storage. Shelf life follows the supplier's specification, with a retest of microbiology and moisture for older stock.

What is the regulatory status of kaolin clay?

21 CFR 347.10 lists kaolin at 4 to 20 percent as an active ingredient in the OTC skin protectant monograph. 21 CFR 186.1256 describes clay (kaolin) as hydrated aluminum silicate and affirms it as GRAS as an indirect human food ingredient used in making paper and paperboard that contact food. Health Canada's Natural Health Products Ingredients Database lists kaolin with common names including bolus alba, china clay and hydrated aluminum silicate, and non-medicinal purposes including abrasive, absorbent, anticaking agent and suspending agent. 7 CFR 205.605(a) lists kaolin among nonsynthetic substances allowed as ingredients in or on processed products labeled organic.

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