Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs); Color: Reddish-brown, tan, or ochre; Luster: Dull to earthy; Structure: Granular/clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & Geological History

Formed through the accumulation and litification of sand-sized mineral grains or rock fragments. The reddish hue indicates iron oxide cementation. These often form in river beds, deserts, or marine environments across various geological ages from Precambrian to Cenozoic.

Uses & Applications

Used primarily in construction as a building material, paving, or crushed stone for road base. Historically significant for making grindstones and architecture.

Geological Facts

Sandstone accounts for roughly 20-25% of all sedimentary rocks on Earth. The distinct coloring in this specimen is due to hematite or goethite acting as a natural glue between the sand grains.

Field Identification & Locations

Identify in the field by its 'sandpaper' texture and visible bedding or grain structure. Commonly found in eroded canyons, plateaus, and dry riverbeds globally.

Identified on: 4/30/2026

Mode: Standard