sedimentary

Glauconitic Sandstone

Glauconitic Quartz Arenite

Hardness: 6-7 (individual quartz grains), 2 for glauconite matrix; Color: Dull green, olive, or bluish-green with iron staining; Luster: Dull to earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.4-2.8

Hardness: 6-7 (individual quartz grains), 2 for glauconite matrix
Color: Dull green, olive, or bluish-green with iron staining
Luster: Dull to earthy

Identified June 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in marine environments through slow sedimentation and the biochemical alteration of fecal pellets and organic matter in shallow waters. Found in many Cretaceous and Eocene geological formations.

Uses & applications

Historically used as a soil conditioner (Greensand) due to potassium content; also used as a water softener, pigement in paint, or low-grade heavy construction aggregate.

Geological facts

The green color comes from the mineral glauconite, a potassium iron silicate that typically forms in marine settings with low oxygen levels.

Field identification & locations

Identify by its distinctive green-tinted sandy texture and tendency to crumble into 'greensand'. Commonly found in coastal plains and sedimentary basins like the Atlantic Coast of the US.