The facts
What fuller's Earth actually is
Fuller's Earth is classified as a general term for absorbent clays - chiefly palygorskite/attapulgite and calcium montmorillonite - used for their adsorptive and decolourising capacity rather than a defined mineral, with the composition Palygorskite (Mg,Al)2Si4O10(OH).4H2O, and/or calcium montmorillonite. It crystallises in the aggregate (monoclinic palygorskite is fibrous) system.
Colour comes from grey-green, buff and cream; the name comes from 'fulling', the historic degreasing of wool, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.50-1.58. Specific gravity around 2.00-2.60. Cleavage: fibrous habit in palygorskite. Those three numbers separate it from most of what imitates it.
Where fuller's Earth comes from
Fuller's Earth is produced at Attapulgus, Georgia and Quincy, Florida, USA - the type area for attapulgite, Redhill and Nutfield, Surrey, England (historic, now closed), Lebrija and the Guadalquivir basin, Spain, Kutch, Gujarat and Rajasthan, India (multani mitti) and Senegal and Ukraine.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How fuller's Earth is treated
Dried, crushed, graded and often acid-activated for edible-oil bleaching. Uses: bleaching and decolourising vegetable and mineral oils, oil and grease absorbent granules, cat litter, pesticide and fertiliser carriers, drilling fluid in salt-saturated systems where bentonite fails, and as a cosmetic clay. HEALTH: palygorskite is a fibrous silicate, and long-fibre varieties have raised concerns analogous to asbestos - IARC treats long-fibre attapulgite as possibly carcinogenic, and dust control is warranted. Also used as a decontaminant for chemical warfare agents.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What fuller's Earth is confused with
In the trade fuller's Earth is most often mistaken for, or substituted by, Bentonite, Kaolin, Sepiolite (the other fibrous magnesium clay) or Diatomite as an absorbent.
The separation is rarely a matter of opinion: refractive index 1.50-1.58 and specific gravity 2.00-2.60 settle most of it in a minute, and magnification settles the rest.
What fuller's Earth is used for
Demand for fuller's Earth comes from heavy industry, filtration, cosmetics, drilling fluids and kitchen and table, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the tonne or by the piece.
Durability and care
Fuller's Earth is 1-2 on the Mohs scale, with fibrous habit in palygorskite cleavage.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What fuller's Earth costs
As a guide, fuller's Earth trades around $150-400 per tonne; activated bleaching earth $300-700 per tonne.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is fuller's Earth treated, and how?
Dried, crushed, graded and often acid-activated for edible-oil bleaching. Uses: bleaching and decolourising vegetable and mineral oils, oil and grease absorbent granules, cat litter, pesticide and fertiliser carriers, drilling fluid in salt-saturated systems where bentonite fails, and as a cosmetic clay. HEALTH: palygorskite is a fibrous silicate, and long-fibre varieties have raised concerns analogous to asbestos - IARC treats long-fibre attapulgite as possibly carcinogenic, and dust control is warranted. Also used as a decontaminant for chemical warfare agents.
Where does fuller's Earth come from?
Attapulgus, Georgia and Quincy, Florida, USA - the type area for attapulgite, Redhill and Nutfield, Surrey, England (historic, now closed), Lebrija and the Guadalquivir basin, Spain, Kutch, Gujarat and Rajasthan, India (multani mitti) and Senegal and Ukraine. Origin affects price, so we name the locality rather than the country on every quote.
Is fuller's Earth hard enough to wear every day?
Not really. At 1-2 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does fuller's Earth cost?
Indicatively $150-400 per tonne; activated bleaching earth $300-700 per tonne. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is fuller's Earth confused with?
Most often Bentonite, Kaolin, Sepiolite (the other fibrous magnesium clay) and Diatomite as an absorbent. A refractive index of 1.50-1.58 and a specific gravity near 2.00-2.60 separate it quickly.
What is fuller's Earth used for besides jewellery?
heavy industry, filtration, cosmetics, drilling fluids and kitchen and table. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for fuller's earth?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about fuller's earth