Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs); Color: Tan, brown, reddish-orange; Luster: Dull/Earthy; Crystal Structure: Clastic, granular texture; 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 appears iron-stained, suggesting oxidation during or after deposition in a terrestrial or shallow marine environment.

Uses & Applications

Commonly used in construction for flagstone, paving, and retaining walls. Crushed sandstone is used in road base and glass manufacturing.

Geological Facts

Sandstone represents about 20% of all sedimentary rocks on Earth and is a primary aquifer and petroleum reservoir due to its porosity.

Field Identification & Locations

Identify by its 'sandpaper' feel and visible grains. Often found in riverbeds, cliffs, and desert outcrops. It can be scratched by steel but will scratch copper.

Identified on: 4/20/2026

Mode: Standard