sedimentary

Red Sandstone (Siltstone pebble)

Arenite / Siltstone (Silicon dioxide based with hematite impurities)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Dull reddish-purple to maroon; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.3-2.6

Hardness: 6-7 Mohs
Color: Dull reddish-purple to maroon
Luster: Dull/Earthy

Identified July 21, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Dull reddish-purple to maroon; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.3-2.6

Formation & geological history

Formed through the accumulation, compaction, and cementation of sand-sized mineral particles or rock fragments. The red/purple hue indicates the presence of iron oxide (hematite) during the lithification process, often in arid or fluvial environments.

Uses & applications

Common pebbles like this are used in landscaping, decorative stone mulch, and as natural abrasives. High-quality sandstone is a major building and paving material.

Geological facts

The color suggests it may be part of the 'Old Red Sandstone' or similar formations which date back to the Devonian period (approx. 400 million years ago). Water-worn pebbles like this are often found in riverbeds or on glacial till plains.

Field identification & locations

Identify in the field by its gritty texture and lack of visible crystals. It will not react with acid (unlike limestone). Commonly found in regions with ancient sedimentary basins or glacial deposits.