Glauconite


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Related to Glauconite: Glaucophane, glauconitic sandstone

glauconite

[′glȯ·kə‚nīt]
(mineralogy)
K15(Fe,Mg,Al)4-6(Si,Al)8O20(OH)4 A type of clay mineral; it is dioctohedral and occurs in flakes and as pigmentary material.

Glauconite

 

a mineral, hydrated iron aluminosilicate belonging to the hydromica group. It is characterized by variable and complex chemical composition; its main components are silica (49-56 percent), ferrous and ferric oxides (up to 21 percent), aluminum oxide (up to 18 percent), potassium oxide (up to 10 percent), magnesium oxide (up to 7 percent), and water (up to 13 percent). It crystallizes in the monoclinic system.

The color of glauconite is green (from dark green, almost black, to olive green). Its hardness on the mineralogical scale is 2-3, and its density is 2,200-2,300 kg/m3. Its capacity for absorbing water, as well as for ion exchange, is considerable. It is found among sedimentary rocks as round grains of cryp-tocrystalline structure, less frequently as small crystals of roughly hexagonal shape. It is formed at the bottom of the sea, where it settles as a gel. Cases of the formation of glauconite through the substitution of grains of biotite and other minerals in marine ooze are known. Glauconite is widespread in sedimentary rocks of various ages, mainly Mesozoic and Cenozoic.

Because of its capacity for cation exchange, glauconite is used to soften water and, since it contains a considerable amount of potassium oxide, as a soil fertilizer. It is also used for making green paint.

References in periodicals archive ?
3), presence of glauconite, biodetrite and maximum of siderite resting in the upper part (Fig.
Besides the characteristic glauconite content, the Leetse Formation is known as the strata where the first conodonts were described, from the same beds in the St.
Coskren (personal communication, 1991) proposes that the glauconite could be a reservoir for nickel.
The shallowest conditions (with Tremadocian conglomerates and sandstones and post-Tremadocian glauconite limestones) were common in the Lublin area in northeastern Poland, to the west of Sarmatia.
The well was drilled to a depth of approximately 9,100 feet (2,750 metres) and was cased as potential Glauconite gas well and an Elkton oil well.
Re-entry of a previously logged and cored well bore has now commenced to drill out cement plugs, complete and test the potential of 10 metres (approximately 32 feet) of oil pay in the Glauconite Channel.
The quartz silt/sandstones, glauconite beds, lime- and dolostones, phosphorite beds as well as black- and oil shale beds were demonstrated and sampled.
Microskeleton composition is: quartz, weathered amphibole, baueritized biotite, plagioclase, chlorite, muscovite, glauconite, microcline, pyroxene.