sedimentary

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

Hardness: 6-7 (on Mohs scale for grain components); Color: Tan, brown, ochre with darker iron/manganese staining; Luster: Dull, earthy; Crystal structure: Granular/clastic; Cleavage: None (fractures around grains); Specific Gravity: 2.2-2.8

Hardness: 6-7 (on Mohs scale for grain components)
Color: Tan, brown, ochre with darker iron/manganese staining
Luster: Dull, earthy

Identified April 3, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments, typically in riverbeds, deserts, or marine environments. This specimen shows signs of secondary mineral precipitation (staining) likely from groundwater mineral transport.

Uses & applications

Commonly used as a building material, decorative stone, for manufacture of glass, and as a reservoir rock for petroleum and water in geological surveys.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The coloring seen in this specimen is likely due to iron oxide minerals such as limonite or hematite infiltrating the porous structure.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible sand grains. It is extremely common worldwide, particularly in basin areas. Collectors look for unique banding patterns like 'Liesegang rings' or fossil inclusions.

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