Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs); Color: Tan, reddish-brown, or orange due to iron oxidation; Luster: Dull/Earthy; Texture: Granular/Sand-like; Porous and clastic.

Formation & Geological History

Formed through the accumulation and cementation of sand-sized mineral grains, mostly quartz and feldspar, in environments like deserts, river beds, or beaches. The reddish tint suggests iron-rich groundwater precipitated hematite or limonite between the grains.

Uses & Applications

Used widely as a construction material (flagstone, building stone), decorative landscaping, and as a reservoir rock for petroleum and water in sub-surface geology.

Geological Facts

Sandstone accounts for about 20% of all sedimentary rocks on Earth. The famous red rock formations in Sedona, Arizona, and the Grand Canyon are primarily composed of ferruginous sandstone layers.

Field Identification & Locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering or bedding planes. It is commonly found in sedimentary basins and eroded canyonlands.

Identified on: 4/24/2026

Mode: Standard