Sandstone (likely Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs scale); Color: Brown, tan, reddish-orange; Luster: Dull, earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & Geological History

Formed through the accumulation and cementation of sand-sized grains, primarily quartz. This specimen is rust-colored due to the presence of iron oxide (hematite or limonite). It typically forms in desert, river, or coastal environments over millions of years.

Uses & Applications

Commonly used as a building material, in decorative masonry, for road gravel, and as a source of quartz for glass making. Collectors value pieces with unique banding or iron stains.

Geological Facts

Sandstone is often the primary reservoir rock for groundwater, oil, and natural gas. Some of the most iconic landscapes in the world, like the Grand Canyon and Petra, are carved from sandstone.

Field Identification & Locations

Identify by its 'sandpaper' texture. Common in sedimentary basins worldwide. When scratched, it should feel gritty and drop tiny grains of sand.

Identified on: 4/25/2026

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