sedimentary

Sandstone Pebble

Arenite (primarily SiO2)

Hardness: 6-7 (if quartz-rich); Color: Tan, brown, or grayish; Luster: Dull or earthy; Crystal structure: Granular/clastic; Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 (if quartz-rich)
Color: Tan, brown, or grayish
Luster: Dull or earthy

Identified March 18, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (if quartz-rich); Color: Tan, brown, or grayish; Luster: Dull or earthy; Crystal structure: Granular/clastic; 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 over millions of years, often in riverbeds, deserts, or coastal environments. This specimen has been rounded by fluvial or tidal erosion.

Uses & applications

Common sandstone is used in construction (crushed stone), glass manufacturing (if high silica), and as decorative landscaping stones. Smooth pebbles like this are often used in home decor or 'worry stones'.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. Its porosity and permeability make it a critical reservoir rock for groundwater, oil, and natural gas.

Field identification & locations

Identify in the field by its distinctive 'sandpaper' feel and visible tiny grains. It is extremely common worldwide in areas where ancient water bodies or deserts once existed. Collectors should look for unique banding or fossils within the layers.