Soils by particle size using the Unified Soils Classification System.

Coarse and fine-grained soils into fifteen descriptive categories from gravels and sands to silts and clays. 

Geotechnical Gauge is a water-resistant 5 x 8in (127 x 203mm) plastic card on a lanyard and has a wealth of information for classification of soils. 

Sand by type from very loose to very dense.

Clays from very soft to hard.

Edges of the card have separate 0-6in and 0-110mm scales.

Six color chips, four patches of sized grains, and four tables assist in classifying.