sedimentary

Glauconite (Sandstone or Shale)

Glauconite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2

AI-generated identification · may be incorrect

Hardness: 2.0 (Mohs scale); Color: Olive green, dull green, to sage green; Luster: Dull to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal; Specific Gravity: 2.4-2.9.

Hardness: 2
Color: Olive green, dull green, to sage green
Luster: Dull to pearly

Identified March 24, 2026More sedimentary →

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Physical properties

Hardness: 2.0 (Mohs scale); Color: Olive green, dull green, to sage green; Luster: Dull to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal; Specific Gravity: 2.4-2.9.

Formation & geological history

Formed in marine environments through slow sedimentation and chemical alteration of organic matter or fecal pellets in shallow continental shelves. Common in Cretaceous and Cenozoic strata.

Uses & applications

Used primarily as a soil conditioner and water softener due to its high potassium and iron content and its cation-exchange capacity. Occasionally used as a green pigment in paints.

Geological facts

Glauconite is often referred to as 'Greensand' and is an indicator of slow-paced sedimentation in a stable marine environment. It is widely used by geologists to date sedimentary sequences.

Field identification & locations

Identify by its distinct green hue and crumbly texture. It is commonly found along coastal regions with exposed ancient seabed, such as the Atlantic Coast of New Jersey. Collectors should look for concentrated green nodules or sandy layers.