Sandstone (with Liesegang rings or Oxidation)

Physical Properties

Hardness: 6-7 (Mohs scale); Color: Grayish-tan exterior with reddish-brown oxidation rings; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None

Formation & Geological History

Formed from the lithification of sand-sized grains deposited in environments like rivers or deserts. The reddish patterns (Liesegang rings) occur when mineral-rich groundwater precipitates iron oxides in the rock pores over thousands of years.

Uses & Applications

Used primarily as construction material, paving stones, and as a source of high-purity silica for glass manufacturing. Smaller, uniquely patterned pieces are popular for amateur rock collecting.

Geological Facts

This specimen displays chemical weathering patterns known as oxidation rinds. The red center is caused by iron 'rusting' within the stone when exposed to moisture and oxygen.

Field Identification & Locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering or staining. It is commonly found in sedimentary basins and canyon walls globally.

Identified on: 4/28/2026

Mode: Standard