Sandstone (Ferruginous)

Hardness: 6-7 (Mohs); Color: Tan, brown, or ochre; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Formed through the accumulation and cementation of sand-sized mineral grains, primarily quartz. The brown color indicates iron oxide (hematite or limonite) acting as a binding agent. They often form in deserts, riverbeds, or marine environments over millions of years.

Commonly used as a building material, for paving stones, grindstones, and in the manufacturing of glass and ceramics.

Sandstone is often porous enough to act as a natural filter for groundwater and can serve as a reservoir for oil and natural gas.

Identify in the field by its gritty texture (feels like sandpaper) and visible bedding planes. Found worldwide in sedimentary basins; look for it in outcrops or as rounded pebbles in streambeds.