What does glauconite mean?
Glauconite is a green, iron-rich silicate mineral associated especially with marine sediments. It forms under conditions of slow sediment accumulation on the seafloor and commonly occurs as tiny grains in sands, shales, and other sedimentary rocks. In some formations, the mineral is abundant enough to give the sediment or weathered material a distinctive green color; thus, unusual green sands may owe their appearance to glauconite. Geologists also value glauconite because its presence and crystal characteristics can help establish the environment and age of sedimentation. The word belongs primarily to specialist vocabulary in geology, mineralogy, soil science, and petroleum exploration rather than general conversation. Its characteristic color and its role as a concentrated source of potassium make it an important mineral in both natural and economic contexts.
nounA green, iron-rich silicate mineral commonly formed in marine sediments. It is often found as grains in sand, shale, and other sedimentary rocks and can be an important source of potassium.
- A soft, earthy green, iron-rich silicate mineral that occurs as grains in marine sedimentary rocks and sands.
"The cliff exposes coarse sand containing abundant grains of glauconite."
"Mineral grains of glauconite help give the ancient sandstone its characteristic greenish color."
"Geologists used the abundance of glauconite in the sediment to date the rock formation more precisely."
Rare and usually used when referring to individual mineral grains or a countable collection of specimens.
"The analyst separated several glauconites from the sand and examined them under magnification."
Some beaches are literally green: their sand can owe its unusual color to millions of tiny glauconite grains formed on the seafloor.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does glauconite come from?
The name derives through the European mineralogical tradition, particularly German Glaukonit and French glauconite, from Ancient Greek glaukos, a term associated with a blue-green or gleaming color. The suffix -ite identifies the substance as a mineral. Related English words such as glaucoma, glaucous, and glaucescent also reflect the Greek color root, although they developed independently of the mineral name.
Related word forms
How glauconite is actually used
The term is specialized, chiefly used in geology, mineralogy, soil science, and petroleum exploration. It is normally treated as a mass noun, with plural forms used only when individual grains or discrete quantities are intended.
Easily confused with glauconite
Glauconite is the individual green mineral, whereas glaucony is a green marine sediment or rock composed largely of glauconite grains.
Glaucophane is a blue to blue-green amphibole mineral, while glauconite is an iron-rich sheet silicate formed chiefly in marine sedimentary environments.