sedimentary

Sandstone (Ferruginous)

Arenite (SiO2 with iron oxide impurities)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Yellowish-brown, tan, or ochre due to iron oxides; Luster: Dull, earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Yellowish-brown, tan, or ochre due to iron oxides
Luster: Dull, earthy

Identified April 6, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Yellowish-brown, tan, or ochre due to iron oxides; Luster: Dull, earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The tan/yellow coloring suggests oxidation of iron-bearing minerals (limonite/goethite) within the rock matrix. Most occur in marine or desert environments over millions of years.

Uses & applications

Commonly used as a building material, in landscaping, and as a source of silica for glass manufacturing. It is also an important reservoir rock for water and petroleum.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The famous Red Rocks of Colorado and the structures of Petra are primarily sandstone.

Field identification & locations

Identify by its 'sandpaper' feel and visible grains. It is commonly found in river beds, cliffs, and desert outcrops. For collectors, look for unique weathering patterns or fossils within the layers.