The Geotechnical Gauge is a water-resistant 5x8in (127x203mm) plastic card on a lanyard and has a wealth of information for classification of soils. Six color chips, four patches of sized grains, and four tables assist in classifying:
• 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.
• Sand by type from very loose to very dense.
• Clays from very soft to hard.
Categories are defined by appearance, by handling properties, or by ranges of field and laboratory test results. Edges of the card have separate 0-6in and 0-110mm scales.