sedimentary

Glauconite (Greensand Articulated Sandstone)

Glauconite ((K, Na)(Fe, Al, Mg)2(Si, Al)4O10(OH)2)

AI-generated identification · may be incorrect

Hardness: 2.0; Color: Olive green, black-green, or brownish if weathered; Luster: Dull to earthy; Crystal structure: Monoclinic; Cleavage: Perfect; Specific gravity: 2.4-2.95

Hardness: 2
Color: Olive green, black-green, or brownish if weathered
Luster: Dull to earthy

Identified June 14, 2026More sedimentary →

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Physical properties

Hardness: 2.0; Color: Olive green, black-green, or brownish if weathered; Luster: Dull to earthy; Crystal structure: Monoclinic; Cleavage: Perfect; Specific gravity: 2.4-2.95

Formation & geological history

Formed in marine environments through the alteration of minerals or organic matter on the seafloor, typically in shallow shelf waters with slow sedimentation rates. Often Cretaceous to Tertiary in age.

Uses & applications

Used as a water softener, a slow-release fertilizer for potassium, and historically as a green pigment in paints.

Geological facts

Known as greensand, it is often used as a geological marker to indicate ancient marine conditions and slow deposition environments.

Field identification & locations

Identify by its characteristic dark green to black-green color and sandy/crumbly texture. Commonly found in coastal plain sedimentary deposits (e.g., New Jersey, USA).