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What is Vermiculite?

Crude and Exfoliated Vermiculite

Vermiculite is the geological name given to a group of hydrated laminar minerals which are aluminium-iron-magnesium silicates, resembling mica in appearance. Rock and other impurities are removed from the crude ore which is then crushed and sorted into sizes. Vermiculite is a safe inert material and is light in colour. When heated it expands (exfoliates) up to 30 times its original volume. The exfoliation process converts the dense flakes of ore into lightweight porous granules containing innumerable minute air layers. Exfoliated (expanded) vermiculite is light and clean to handle, has a high insulation value, acoustic-insulating properties and will absorb and hold a wide range of liquids.

 Downloads
Download PDF file Vermiculite Data Sheet (364 KB)
Download PDF file Vermiculite Material Safety Data Sheet (101 KB)

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These granules are non-combustible, and are insoluble in water and all organic solvents. Expanded vermiculite is easily poured, is light, clean, highly absorbent and provides baffle against impact shock when used for packaging.

Exfoliated vermiculite is used in the friction brake linings market, high temperature insulation, loft insulation, various construction products, animal feeds, horticulture and many other industrial applications. Vermiculite with its layered structure and surface characteristics, is utilised in products such as intumescent coatings and gaskets, the treatment of toxic waste and air-freight packaging of hazardous goods.

Typical Properties


Chemical Analysis
Silicon (SiO2)39.4%
Magnesium (MgO)25.2%
Aluminium (Al2O3)8.8%
Potassium (K2O)4.5%
Iron (Fe2O3)4.0%
Calcium (CaO)1.8%
Carbonate (CO2)1.4%
Titanium (TiO2)0.8%
Fluorine (F)0.5%
Physical Properties
Melting Point (°C)1330
Specific Heat (1kJ/kg.K)1.08
Specific Gravity (Crude)2.5
Mohs Hardness (Crude)1 - 2
pH (ISO 787-9)7 - 8
% Loss at 105°C (Expanded Product)< 0.5
% Loss at 1000°C (Expanded Product)< 6

The above product information is given in good faith as accurate and reliable but is not to be taken as a guarantee. The figures provided are intended to be a guide to expected average values and should not be interpreted as a specification. Any potential applications referred to are not to be construed as recommendations. It is the responsibility of the user to determine suitability for any specific purpose.