sedimentary

Silty Sand / Loam

Unconsolidated Clastic Sediment (Silicon Dioxide / Alumino-silicates mixture)

Hardness: Variable based on individual grains (typically 6.5-7 for quartz grains); Color: Tan, beige, or brownish-gray; Luster: Dull or earthy; Structure: Granular and loose; Specific Gravity: 1.5 - 2.0 (bulk density).

Hardness: Variable based on individual grains (typically 6
Color: Tan, beige, or brownish-gray
Luster: Dull or earthy

Identified February 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the mechanical weathering of parent rocks like granite or sandstone. It is typically deposited in alluvial (floodplains), aeolian (wind), or lacustrine (lake) environments during the Quaternary period.

Uses & applications

Used primarily in construction for fill dirt, as a base for pavers, in agricultural soil mixes, and in the manufacturing of bricks or ceramic tiles.

Geological facts

Loamy soil containing silty sand is often referred to as the 'ideal' agricultural soil because it retains moisture better than pure sand but drains more effectively than pure clay.

Field identification & locations

Identify in the field by its gritty texture when rubbed between fingers; it will not hold a structural shape or 'ribbon' when wet like clay does. Found globally in river valleys and plateaus.

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

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Sandstone

Arenite (primarily SiO2)

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Shale or Slaty Mudstone

Argillaceous sedimentary rock

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Chert Breccia

Brecciated Chert (Microcrystalline Silica)

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Sandstone (Quartz-rich)

Arenite (SiO2)

sedimentary

Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

sedimentary