sedimentary
Glauconitic Sandstone
Glauconitic sandstone ((K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Hardness: 2-3 (glauconite) to 7 (quartz matrix), Color: Dull green to dark olive green, Luster: Earthy to dull, Structure: Granular or pelletal, Cleavage: None (in sedimentary form)
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Physical properties
Hardness: 2-3 (glauconite) to 7 (quartz matrix), Color: Dull green to dark olive green, Luster: Earthy to dull, Structure: Granular or pelletal, Cleavage: None (in sedimentary form)
Formation & geological history
Formed in marine environments through the slow accumulation of organic matter and chemical precipitation on the continental shelf. It often dates to the Cretaceous or Cenozoic eras.
Uses & applications
Used primarily as a soil conditioner (greensand) due to potassium content, a water softener, and occasionally as a low-grade pigment or for light construction fill.
Geological facts
Glauconite is often referred to as 'greensand.' It is an indicator of slow sedimentation rates in marine settings and is frequently used by geologists to identify paleo-shorelines.
Field identification & locations
Identify by its distinctive dull green color and sandy texture; it often stains fingers green when rubbed. Commonly found in coastal plain regions like New Jersey and the UK.
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