Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs scale), Color: Brownish-tan to rusty orange, Luster: Dull/Earthy, Crystal Structure: Granular/Clastic, Cleavage: None, Specific Gravity: 2.2-2.8

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral grains or rock fragments. The brown coloration suggests iron oxide (hematite or goethite) cementation. Formed in high-energy environments like beaches, deserts, or riverbeds.

Uses & Applications

Commonly used as a construction material, for paving, grindstones/whetstones, and in glass manufacturing if silica content is high.

Geological Facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. It is a major reservoir for groundwater and petroleum because of its porosity.

Field Identification & Locations

Identify by its 'sandpaper' feel and visible grains. Often found in layered outcrops. Collectors should look for unique cross-bedding patterns or fossil inclusions.

Identified on: 4/20/2026

Mode: Standard