Geotechnical Classification Charts

Gilson’s selection of color and grain size charts and gauges are standard tools used by geologists, civil engineers, soil scientists, and other technicians in the visual and textural field classification of soils. The charts are a guide for the classification of size, shape, color, and density characteristics of soils from sands and gravels to silts and clays. Specific products were developed as classification tools in accordance with the U.S. Soil Conservation Service, the Unified Soils Classification System, and the Wentworth Grading Scale.


Munsell Soil Color Book
Model: HM-519
Sand Grain Size Chart
Model: HM-510
Geotechnical Gauge
Model: HM-512
Sand Gauge
Model: HM-513
Geotechnical Classification Charts
  • Munsell Soil Color Charts developed by the U.S. Soil Conservation Service classify soil colors and are also used in the classification of natural products such as rocks, archeological specimens, and more.
  • Grain Size Chart classifies particles in accordance with the Wentworth Grading Scale. Particles are identified in six ranges from silt to very coarse sands.
  • Geotechnical Gauge identifies soils by particle size utilizing the Unified Soils Classification System. It further categorizes a range of soil, sand, gravel, silt, and clay types into 15 different categories.
  • Sand Gauge contains nine sand grain patches used in the identification of particle size and roundness. This handheld gauge helps field technicians determine bed thickness and additional field classifications.

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