sedimentary

Sandstone Pebble

Arenite (primarily SiO2)

Hardness: 6-7 on Mohs scale; Color: tan, yellowish-brown with dark speckles; Luster: dull to earthy; Texture: grainy/gritty like sandpaper; Specific gravity: approx. 2.2-2.8.

Hardness: 6-7 on Mohs scale
Color: tan, yellowish-brown with dark speckles
Luster: dull to earthy

Identified April 12, 2026More sedimentary →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: tan, yellowish-brown with dark speckles; Luster: dull to earthy; Texture: grainy/gritty like sandpaper; Specific gravity: approx. 2.2-2.8.

Formation & geological history

Formed from the accumulation and cementation of mineral particles or rock fragments (sand-sized grains), typically in riverbeds, deserts, or marine environments. This specimen shows significant rounding typical of fluvial (river) erosion.

Uses & applications

Common sandstone is used in construction (building stone, pavers) and as a source for silica in glassmaking. Small pebbles are used in landscaping and as aggregate in concrete.

Geological facts

Sandstone accounts for approximately 20% of all sedimentary rocks on Earth. The dark speckles in this specimen are likely iron or manganese oxide inclusions or small bits of organic matter trapped during sedimentation.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper when rubbed) and visible sand grains. Found globally in basins and along coastlines. Common in sedimentary outcrops.