Sandstone (with Lichen)

Physical Properties

Hardness: 6-7 (individual quartz grains); Color: Tan, beige, brown, and weathered grey; Luster: Dull/Earthy; Crystal Structure: Clastic (composed of cemented grains); Cleavage: None; Specific Gravity: 2.2 - 2.8.

Formation & Geological History

Formed through the accumulation, compaction, and cementation of sand-sized mineral grains or rock fragments (weathering products). Common in desert, river, and marine environments over millions of years.

Uses & Applications

Extensively used as a building stone, paving material, and in the production of glass (if high purity quartz). Also a major reservoir for groundwater and petroleum.

Geological Facts

Sandstone reveals much about earth history, reflecting past environments such as ancient dunes or riverbeds. The white and yellow spotting on the surface is not a mineral part of the rock, but crustose lichen, a symbiotic organism of algae and fungi.

Field Identification & Locations

Identify in the field by its gritty 'sandpaper' feel and visible layers (bedding). It is found worldwide in sedimentary basins. Collectors often look for colorful 'wonderstone' varieties or those containing fossils.

Identified on: 4/26/2026

Mode: Standard