Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs); Color: Brown/tan due to iron oxide staining; Luster: Dull/earthy; Crystal structure: Clastic (sand-sized grains); 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. Most often formed in deserts, riverbeds, or beaches over millions of years.

Uses & Applications

Used primarily as a building material, masonry, and for paving. Historically significant for making grindstones and tools. Some varieties are used in decorative landscaping.

Geological Facts

Sandstone makes up about 20% to 25% of all sedimentary rocks on Earth. The famous red rock formations in Sedona, Arizona and the Grand Canyon are primarily composed of sandstone layers.

Field Identification & Locations

Identify in the field by its 'sandpaper' texture and visible small grains. It often feels gritty to the touch and can be found in layered outcrops or as river-worn cobbles.

Identified on: 4/25/2026

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