Sandstone

Physical Properties

Hardness: 6-7 Mohs; Color: Brown, tan, and dark grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None/Irregular fracture; Specific gravity: 2.2-2.8

Formation & Geological History

Formed by the accumulation and lithification of sand-sized mineral grains or rock fragments, typically in river beds, beaches, or deserts. This specimen shows signs of iron oxide staining and potential secondary mineralization.

Uses & Applications

Used extensively in construction as building stone, pavers, and crushed stone; historically used for grindstones and in glass manufacturing if high in silica.

Geological Facts

Sandstone represents about 20% of all sedimentary rocks on Earth. It acts as a major reservoir for groundwater and petroleum due to its high porosity and permeability.

Field Identification & Locations

Identify in the field by its gritty 'sandpaper' texture and visible mineral grains. Commonly found in sedimentary basins and exposed canyon walls. Use a magnifying glass to see the individual cemented grains.

Identified on: 5/14/2026

Mode: Standard