Sandstone (likely Greywacke or Siltstone variety)

Physical Properties

Hardness: 6-7 Mohs; Color: Grey/light brown with speckled weathering; Luster: Dull/Earthy; Structure: Clastic, fine-grained; Cleavage: None (conchoidal to irregular fracture); Specific Gravity: 2.2–2.8

Formation & Geological History

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. This specimen likely formed in a marine shelf environment where tectonic activity introduced mixed lithic fragments (Greywacke).

Uses & Applications

Used primarily as aggregate in construction, road base, and occasionally as dimension stone for landscaping or building veneers if the bedding is stable.

Geological Facts

Sandstone is one of the most common sedimentary rocks in the Earth's crust. It is highly porous and often acts as a natural aquifer or a reservoir for petroleum and natural gas.

Field Identification & Locations

Identify by its gritty texture (feels like sandpaper) and visible layering or bedding planes. It is commonly found in sedimentary basins, canyons, and mountainous regions worldwide.

Identified on: 4/19/2026

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