Sandstone (Pebble)

Physical Properties

Hardness: 6-7 Mohs; Color: Greyish-tan with white mineral clasts; Luster: Dull/Earthy; Structure: Fine-grained clastic texture; Cleavage: None (conchoidal fracture on fresh surfaces).

Formation & Geological History

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments, typically in riverbeds, beaches, or deserts. High degree of rounding indicates significant transport by water.

Uses & Applications

Used in construction, as a landscaping material, and as an abrasive in industrial processes. Polished river stones are used for decorative flooring and massage therapy.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. This specific specimen is a 'river rock' or 'cobble' that has been naturally tumbled and smoothed by hydraulic action over thousands of years.

Field Identification & Locations

Identify in the field by its gritty texture (feels like sandpaper) and visible grains. Commonly found in alluvial deposits, stream beds, and near coastal areas.

Identified on: 4/30/2026

Mode: Standard