Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (individual grains), 4-5 (matrix); Color: Tanish-brown to reddish-brown; Luster: Dull/Earthy; Crystal 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, typically in desert, river, or coastal environments. Reddish hues indicate oxidation of iron minerals during burial.

Uses & Applications

Commonly used as a building material, for paving stones, grindstones, and as a reservoir rock for oil, gas, and groundwater. Ferruginous varieties are rarely used for jewelry but are popular in landscaping.

Geological Facts

Sandstone accounts for approximately 20-25% of all sedimentary rock on Earth. Famous landmarks like the Grand Canyon and Petra are primarily composed of various sandstone formations.

Field Identification & Locations

Identify by a gritty 'sandpaper' feel when rubbed. It often shows layering (bedding). This specific specimen appears to be a weathered, iron-rich terrestrial fragment.

Identified on: 4/20/2026

Mode: Standard