Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs scale), Color: Reddish-brown, tan, and grey, Luster: Dull/Earthy, Crystal Structure: Granular/Clastic, Cleavage: None, 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 shows distinct bedding planes, typical of deposition in riverbeds or shallow seas. Age can range from millions to over a billion years depending on locality.

Uses & Applications

Used widely as a building material, in the manufacture of glass (if high silica), for paving stones, and as an aquifer for water and oil reservoirs.

Geological Facts

Sandstone makes up about 10-20% of Earth's sedimentary rocks. The distinct banding seen here represents different flow regimes or mineral pulses during its original deposition.

Field Identification & Locations

Field identification: Look for sand-like grains that feel gritty to the touch (like sandpaper). Common in desert environments, plateaus, and river basins. Collectors look for unique banding or fossil inclusions.

Identified on: 4/19/2026

Mode: Standard