Sandstone

Physical Properties

Hardness: 6-7 Mohs (quartz-based); Color: Tan, beige, or yellow-brown; Luster: Dull/Earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral particles or rock fragments. This specimen appears to be a water-worn river pebble, likely shaped over thousands of years by fluvial erosion.

Uses & Applications

Used extensively in construction as a building material, road base, or decorative stone. In industry, high-purity sandstones are used for glassmaking.

Geological Facts

Sandstone accounts for approximately 20% of all sedimentary rocks on Earth. It often acts as a significant reservoir for underground water, oil, and natural gas due to its porosity.

Field Identification & Locations

Identify by its gritty, sandpaper-like feel and the visible small grains. Commonly found in riverbeds, deserts, and coastal areas. It is one of the most common rocks for beginning collectors to find.

Identified on: 4/30/2026

Mode: Standard