Sandstone (Ferruginous)

Physical Properties

Hardness: 6-7 (Mohs); Color: Tan, brown, or reddish due to iron oxide; Luster: Dull/Earthy; Crystal structure: Clastic (granular texture); Cleavage: None; Specific Gravity: 2.2 - 2.8

Formation & Geological History

Formed through the accumulation and cementation of mineral particles or rock fragments (clasts) that are the size of sand grains. This specimen likely formed in a riverbed or desert environment where iron oxide acted as a natural cement.

Uses & Applications

Commonly used in construction as building stone or as a source of industrial sand (silica) for glassmaking. Also used for decorative landscaping.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The famous red rocks of the Grand Canyon and Petra in Jordan are primarily made of this rock type.

Field Identification & Locations

Identify in the field by its gritty 'sandpaper' feel when rubbed. Found globally in basins and mountainous regions. For collectors, look for unique weathering patterns or layering.

Identified on: 4/22/2026

Mode: Standard