sedimentary
Glauconitic Sandstone (Greensand)
Glauconitic quartz wacke or arenite
Hardness: 2-3 (glauconite) to 7 (quartz grains); Color: Dull olive green to brownish/gray; Luster: Earthy to dull; Structure: Granular/clastic; Cleavage: None (friable).
- Hardness
- 2-3 (glauconite) to 7 (quartz grains)
- Color
- Dull olive green to brownish/gray
- Luster
- Earthy to dull
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Physical properties
Hardness: 2-3 (glauconite) to 7 (quartz grains); Color: Dull olive green to brownish/gray; Luster: Earthy to dull; Structure: Granular/clastic; Cleavage: None (friable).
Formation & geological history
Formed in marine environments on continental shelves through the slow deposition of sediments and the biochemical alteration of fecal pellets and organic matter into glauconite, often during the Cretaceous or Tertiary periods.
Uses & applications
Historically used as a soil conditioner and slow-release potash fertilizer; also used in water softening and as a decorative building stone in certain regions.
Geological facts
Greensand is famously known for containing a high density of marine fossils, including shark teeth and ancient mollusks. The green color is a key indicator of slow sedimentation rates in geological history.
Field identification & locations
Identify by its distinctive olive-green color and sandy texture that easily rubs off into grains. Often found in coastal plain regions like the Eastern United States (New Jersey/Maryland) or Southeastern England.
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