sedimentary
Glauconite (Sandstone or Shale)
Glauconite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2
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 More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
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.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary