Limonitic Sandstone (Stained Sandstone)

Physical Properties

Hardness: 6-7 (individual quartz grains), Color: Yellow-ochre to rusty brown, Luster: Dull or earthy, Crystal structure: Granular/Clastic, Cleavage: Indistinct, Specific Gravity: 2.3-2.6

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral grains or rock fragments. The distinct yellow-orange color is due to the chemical weathering of iron-bearing minerals, creating iron oxide (limonite) staining on the grain surfaces.

Uses & Applications

Common sandstone is used in construction as building stone, flagstone, or crushed stone for road bases. Varieties with high iron content were historically used as iron ore pigments (yellow ochre).

Geological Facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. The color of sandstone is often a direct result of the chemical environment during its formation or subsequent weathering.

Field Identification & Locations

Identify in the field by its gritty texture (feels like sandpaper) and visible grains. The yellow-orange color is a diagnostic indicator of oxidation. Look for bedding planes or layers which are common in these deposits.

Identified on: 4/16/2026

Mode: Standard