Introducing our Particle Size Indicator

We are pleased to present our new Particle Size Indicator which Geolabs have developed in partnership with Professor David Norbury, Professor in Engineering Geology at Sussex University.

The Geolabs Particle Size Indicator makes it easier to assess the sizes of particles in a soil sample on site and in the laboratory.

Graded samples of sands and silt are secured on to a stiff board to allow a direct visual comparison to those different sizes of materials and an indication of fine, medium and coarse sands.

Gravels can be assessed by trying to pass the particle through the square holes in the card. For example, a piece of medium gravel would pass through the 20 mm medium gravel hole, but not the 6 mm fine gravel hole. If a large particle that you can hold in your hand will not fit through the 63 mm large gravel hole, then it is a cobble.

For the larger sizes, read-off the sieve sizes they would have to fit through the right-hand end of the card. For example, a large boulder would not pass through a 630 mm square sieve, whereas a boulder would pass through that but get trapped by a 200 mm hole.

The Indicator has been accepted and used by all those working within the geotechnical fraternity, from drillers, engineers, environmentalists, technicians and academia.

If you haven’t already received one, please email your request to

If you are on site and are using one of our Particle Size Indicators, we would love to see a photo of you using it insitu. Feel free to also upload one directly to our Twitter page @GeolabsLimted #particlesize or on our LinkedIn page.

We would be pleased to hear any feedback or any further recommendations or advice for improvements that you may have. It is our intention in the future to reproduce the Indicator in a plastic or similar format, to improve its robustness and long-term viability for usage on sites and during inclement weather.

Danielle Pullen, Eng. Geologist – Frederick Sherrell Ltd

Danielle Pullen, Eng. Geologist – Frederick Sherrell Ltd

submitted by Danielle Pullen, Frederick Sherrell Ltd

submitted by Danielle Pullen, Frederick Sherrell Ltd