Sandstone (likely Fossiliferous)

Physical Properties

Hardness: 6-7 (on Mohs scale); Color: Tan, brown, reddish-brown; Luster: Dull/Earthy; Crystal structure: Clastic (grains of sand); Cleavage: None; Specific Gravity: 2.2–2.8.

Formation & Geological History

Formed through the accumulation and cementation of mineral particles or rock fragments (sand) in marine or terrestrial environments. The presence of inclusions suggests a bioclastic or fossil-rich deposit from a shallow sea or river bed.

Uses & Applications

Construction material, glass manufacturing (if high silica), architectural stone, and geological research.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. It is a major aquifer and oil reservoir rock due to its high porosity and permeability. Some of the world's most famous natural arches and canyon walls are made of sandstone.

Field Identification & Locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering (bedding). Look for fossil imprints or small mineral inclusions. Common in arid regions, coastal cliffs, and river basins.

Identified on: 4/26/2026

Mode: Standard