The Science Behind Vermiculite
Vermiculite is a member of the phyllosilicate group of minerals, resembling mica in appearance, and is a hydrous phyllosilicate mineral that undergoes significant expansion when heated.
Vermiculite’s inner laminar layers allow it to expand up to 50% in volume which allows it to be highly aerated. This property also allows for high water absorption and retention. It is very pH neutral and has natural elements of Potassium and Magnesium which are favorable in the horticultural and animal feed industries.


Crude vermiculite consists of thin golden to brown flakes containing microscopic layers of water which are carefully classified into five grades – each with a specified range of particle sizes. Crude vermiculite is at times used in animal feed pre-mixes due to its flowability.
Our vermiculite is registered under Act 36 of 1947 in line with the Department of Agriculture, Forestry, and Fisheries.

Packaging
Bulk Bags
Act 36 Registered
V-Number: V28079
Available Grades

Applications
- Insulation
- Concrete
- Refractories
- Packaging
Particle Size
- 2-8 mm
- Screened to be dust free
Packaging
- 100 litre pre-packed bags
- Palletised
Volume Yield
- 13-14.5%
Density
- 75-90 kg/m3

Applications
- Insulation
- Horticulture
- Refractories
Particle Size
- 1.4 – 4.0 mm
- Screened to be dust free
Packaging
- 100 litre pre-packed bags
- Palletised
Volume Yield
- 10.5 – 13.0%
Density
- 85-105 kg/m3

Applications
- Horticulture
- Friction
- Screened to be dust free
Particle Size
- 0.7 – 2.0 mm
- Screened to be dust free
Packaging
- 100 litre pre-packed bags
- Palletised
Volume Yield
- 8.5 – 11.5%
Density
- 95-115 kg/m3

Applications
- Animal Feed
- Friction
- Screeds
Particle Size
- 0.35 – 1.0 mm
- Screened to be dust free
Packaging
- 100 litre pre-packed bags
- Palletised
Volume Yield
- 7.5 – 10.0%
Density
- 115 – 130 kg/m3

Applications
- Animal Feed
- Friction
Particle Size
- 0.25 – 0.75 mm
- Screened to be dust free
Packaging
- 100 litre pre-packed bags
- Palletised
Volume Yield
- 6.5 – 9.0%
Density
- 115 – 130 kg/m3
Package Properties
Grade | Particle size distribution min. 80% retained (mm) | Loose bulk Density kg/m3 |
Large | -8.0 + 2.8 | 700 – 850 |
Medium | -4.0 + 1.4 | 800 – 950 |
Fine | -2.0 + 0.710 | 850 – 1050 |
Superfine | -1.0 + 0.355 | 850 – 1050 |
Micron | -0.710 + 0.250 | 850 – 1050 |
Chemical Properties
SiO2 | 32 |
MgO | 25.5 |
Al2O3 | 10 |
K2O | 6 |
Fe2O3 | 9.5 |
CO2 | 2.5 |
CaO | 17.17 |
TiO2 | 1.4 |
P4O10 | 1.4 |
Other Properties
Specific Gravity: +-2.75 kg/m3
Moh’s Hardness: 1-2
Exfoliated or expanded vermiculite consists of accordion-like granules containing microscopic air layers full of mineral water in a crude state. At high temperatures this water vaporizes, causing the material to expand. The layers are pressed apart, resulting in a harmonica structure to which vermiculite owes its lightweight and excellent insulation properties.