sedimentary

Glauconitic Sanstone (Glauconite)

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

AI-generated identification · may be incorrect

Hardness: 2 Mohs; Color: Dull green, olive green, or blackish green; Luster: Dull to pearly; Crystal Structure: Monoclinic; Cleavage: Perfect basal; SG: 2.4-2.95

Hardness: 2 Mohs
Color: Dull green, olive green, or blackish green
Luster: Dull to pearly

Identified June 3, 2026More sedimentary →

Explore Glauconitic Sanstone (Glauconite) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 2 Mohs; Color: Dull green, olive green, or blackish green; Luster: Dull to pearly; Crystal Structure: Monoclinic; Cleavage: Perfect basal; SG: 2.4-2.95

Formation & geological history

Formed in marine environments through the alteration of minerals like mica and fecal pellets on the seabed during periods of slow sedimentation. Typically found in deposits from the Paleozoic to the present.

Uses & applications

Used primarily as a soil conditioner and source of potassium (greensand) in organic farming. Historically used as a green pigment for paints.

Geological facts

Glauconite is a 'facies indicator' meaning its presence tells geologists that the area was once a shallow, marine environment with slow sediment accumulation. It is often responsible for the green color in 'greensand' formations.

Field identification & locations

Identified in the field by its distinct green color and sandy or pelletal texture. It is often soft and can be crushed to a powder. Found in coastal regions like New Jersey (USA), England, and Australia.