Sandstone (likely Graywacke or Arkose variant)

Physical Properties

Hardness: 6-7 Mohs; Color: Grayish-green to tan; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2–2.8

Formation & Geological History

Formed through the accumulation and cementation of mineral particles or rock fragments. This specimen appears to be a lithic sandstone, likely formed in a marine or river environment where sand-sized grains were compressed over millions of years.

Uses & Applications

Commonly used in construction as a building material, for paving, or as crushed stone. Also used in glass manufacturing if silica content is high enough.

Geological Facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. It is a major reservoir for groundwater and petroleum because of its porosity.

Field Identification & Locations

Identify in the field by its 'sandpaper' feel and visible grains. It will not fizz with acid unless it has a calcitic cement. Found globally in basins and coastal regions.

Identified on: 4/24/2026

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