Sandstone

Physical Properties

Hardness: 6-7 (on Mohs scale); Color: Tan, brown, or beige with reddish speckles; Luster: Dull/Earthy; Crystal structure: Clastic (matrix of rounded sand grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral grains or rock fragments over millions of years. Usually found in desert, river, or ocean environments where high-energy water or wind deposits sand.

Uses & Applications

Predominantly used as a building material, paving stone, in the production of glass (if high quartz content), and as a reservoir rock for petroleum and groundwater.

Geological Facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. Famous landmarks like the Grand Canyon and the Nabataean city of Petra are carved into sandstone formations.

Field Identification & Locations

Identify in the field by its gritty, sand-paper-like feel and visible layered bedding. It is common in arid regions and coastal cliffs. Collectors look for unique banding patterns like 'Wonderstone'.

Identified on: 4/19/2026

Mode: Standard