sedimentary

Sandstone (Ferruginous)

Arenite (Iron-rich)

Hardness: 6-7 (on Mohs scale if quartz-based); Color: Reddish-brown, tan, orange; Luster: Dull/Earthy; Crystal structure: Clastic (composed of sand-sized grains); Cleavage: None/Irregular fracture; Specific Gravity: 2.3-2.6

Hardness: 6-7 (on Mohs scale if quartz-based)
Color: Reddish-brown, tan, orange
Luster: Dull/Earthy

Identified April 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized grains, typically quartz or feldspar. The reddish color is due to iron oxide (hematite or goethite) acting as a cementing agent or coating. These specimens can range from hundreds of millions of years old to relatively recent deposits.

Uses & applications

Used widely in construction as a building stone and for road base. In industry, it is a source of silica for glassmaking. Rough specimens are common in geological teaching collections.

Geological facts

Sandstone accounts for about 20% of all sedimentary rocks on Earth. Ferruginous sandstones are specifically known for 'iron-banding' or Liesegang rings in certain geological formations.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture and visible sand grains. It is commonly found in desert environments, river basins, and coastal areas worldwide.