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Glauconite

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Formula:
(K,Na)(Fe
3+
 
,Al,Mg)
 
2
((Si,Al)
 
4
O
 
10
)(OH)
 
2
System:MonoclinicColour:Blue-green, ...
Hardness:2
Member of:Mica Group
Name:Named in 1828 by Christian Keferstein from the Greek "glaukos," blue-green, in allusion to its color; but the term "glauconie" was used earlier, in 1823 by Alexandre Brongniart, as a name for the English term "green sand". Both celadonite and glauconite were lumped with grünerde, the approximate German equivalent of green sand, by Dana (1844). Eventually, glauconite was applied to the sedimentary pellets, with which the species has been tied ever since, although the celadonites were essentially lumped together until the new species of the celadonite sub-group were established in 1997 by Gejing Li, Donald Ralph Peacor, Douglas S. Coombs, and Yosuke Kawachi. Rieder et.al. (1998) kept glauconite as a species in the celadonite sub-group as essentially the ferric-ferric analog of celadonite. Because of the consequent high octahedral charge contribution, the octahedral sites have vacancies and/or lower-charge cation substitutions. The range of interlayer cation site occupancy is defined as 0.6-0.85
Isostructural with:Aluminoceladonite, Celadonite, Chromceladonite, Ferro-aluminoceladonite, Ferroceladonite


Mica Group.

Typically found as rounded aggregates or "pellets" of very fine grained scaly particles, having a blue-green to yellow-green color. True glauconites may have been found in other environments, but, before 1998, may have been classed as celadonite.

Classification of Glauconite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Explanation of status:The name is for a series in the Mica Group, not an individual species. While it is currently accepted, it is likely that once the species in the series have been better defined it will be replaced by two or more species names.
Strunz 8th edition ID:8/H.13-40

8 : Silicates
H : Phyllosilicates (layered), Tetragonal or pseudotetragonal layered structures [Si4O10]4- and others
13 : Mica group - Glauconite series
Dana 7th edition ID:71.2.2.5
Dana 8th edition ID:71.2.2a.5

71 : PHYLLOSILICATES Sheets of Six-Membered Rings
2 : Sheets of 6-membered rings with 2:1 layers
Hey's CIM Ref.:16.20.10

16 : Silicates Containing Aluminum and other Metals
20 : Aluminosilicates of Fe, Mg and alkalis
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Occurrences of Glauconite

Geological Setting:Formed in shallow marine environments that are mildly reducing when little or no sedimentation is taking place, hence found in shallow marine sedimentary rocks - limestones, siltstones, shales and sandstones. "Greensands" are named that because of their typically high glauconite content.

Physical Properties of Glauconite

Lustre:Dull, Earthy
Diaphaneity (Transparency):Translucent, Opaque
Colour:Blue-green, yellow-green, green, rarely colorless.
Streak:None
Hardness (Mohs):2
Hardness Data:Measured
Tenacity:Elastic
Cleavage:Perfect
Perfect on {001}.
Fracture:Micaceous
Density (measured):2.4 - 2.95 g/cm3
Density (calculated):2.9 g/cm3

Crystallography of Glauconite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:B2/m {B1 1 2/m} {C2/m} {C1 2/m 1}
Cell Parameters:a = 5.234Å, b = 9.066Å, c = 10.16Å
β = 100.5°
Ratio:a:b:c = 0.577 : 1 : 1.121
Unit Cell Volume:V 474.03 ų (Calculated from Unit Cell)
Z:2
Morphology:Crystals extremely rare; typically found as rounded aggregates of very fine grained scaly particles, more rarely as tiny laths or platelets.
X-Ray Powder Diffraction:
d-spacingIntensity
10.1(100)
4.53(80)
3.63(400
3.33(60)
3.09(40)
2.59(100)
2.40(60)
1.511(60)
Comments:The -1M and -3T polytypes cannot be distinguished by the powder pattern.

Optical Data of Glauconite

Type:Biaxial (-)
RI values: nα = 1.590 - 1.612 nβ = 1.609 - 1.643 nγ = 1.610 - 1.644
2V:Calculated: 20° to 24°
Maximum Birefringence:δ = 0.020 - 0.032

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r > v

Chemical Properties of Glauconite

Formula:
(K,Na)(Fe
3+
 
,Al,Mg)
 
2
((Si,Al)
 
4
O
 
10
)(OH)
 
2
Simplified for copy/paste:(K,Na)(Fe3+,Al,Mg)2((Si,Al)4O10)(OH)2
Essential elements:Fe, H, K, O, Si
All elements listed in formula:Al, Fe, H, K, Mg, Na, O, Si
Common Impurities:Ti,Ca,P

Relationship of Glauconite to other Species

Member of:Mica Group
Other Members of Group:

- +
Aluminoceladonite
K(Mg,Fe
2+
 
)Al(Si
 
4
O
 
10
)(OH)
 
2
Anandite
(Ba,K)(Fe
2+
 
,Mg)
 
3
((Si,Al,Fe)
 
4
O
 
10
)(S,OH)
 
2
Aspidolite
NaMg
 
3
(AlSi
 
3
O
 
10
)(OH)
 
2
Biotite
Bityite
LiCaAl
 
2
(AlBeSi
 
2
O
 
10
)(OH)
 
2
Boromuscovite
KAl
 
2
(BSi
 
3
O
 
10
)(OH)
 
2
Celadonite
K(Mg,Fe
2+
 
)Fe
3+
 
(Si
 
4
O
 
10
)(OH)
 
2
Chernykhite
(Ba,Na)(V
3+
 
,Al,Mg)
 
2
((Si,Al)
 
4
O
 
10
)(OH)
 
2
Chromceladonite
K(Mg,Fe
2+
 
)(Cr,Al)(Si
 
4
O
 
10
)(OH)
 
2
Chromphyllite
K(Cr,Al)
 
2
(AlSi
 
3
O
 
10
)(OH,F)
 
2
Clintonite
Ca(Mg,Al)
 
3
(Al
 
3
SiO
 
10
)(OH)
 
2
Ephesite
LiNaAl
 
2
(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
Ferro-aluminoceladonite
K(Fe
2+
 
,Mg)(Al,Fe
3+
 
)(Si
 
4
O
 
10
)(OH)
 
2
Ferroceladonite
K(Fe
2+
 
,Mg)(Fe
3+
 
,Al)(Si
 
4
O
 
10
)(OH)
 
2
Ferrokinoshitalite
(Ba,K)(Fe
2+
 
,Mg)
 
3
(Al
 
2
Si
 
2
O
 
10
)(OH,F)
 
2
Ganterite
(Ba,Na,K)(Al,Mg)
 
2
(AlSi
 
3
O
 
10
)(OH)
 
2
Hendricksite
K(Zn,Mg,Mn
2+
 
)
 
3
(AlSi
 
3
O
 
10
)(OH)
 
2
Illite
K
 
0.65
Al
 
2.0
[Al
 
0.65
Si
 
3.35
O
 
10
](OH)
 
2
Kinoshitalite
(Ba,K)(Mg,Mn
2+
 
,Al)
 
3
(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
Lepidolite
Luanshiweiite-2M1
KLiAl
 
1.5
(Si
 
3.5
Al
 
0.5
)O
 
10
(OH)
 
2
Margarite
CaAl
 
2
(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
Masutomilite
(K,Rb)(Li,Mn
3+
 
,Al)
 
3
(AlSi
 
3
O
 
10
)(F,OH)
 
2
Montdorite
(K,Na)
 
2
(Fe
2+
 
,Mn
2+
 
,Mg)
 
5
(Si
 
4
O
 
10
)
 
2
(OH,F)
 
4
Muscovite
KAl
 
2
(AlSi
 
3
O
 
10
)(OH)
 
2
Nanpingite
CsAl
 
2
(AlSi
 
3
O
 
10
)(OH,F)
 
2
Natro-glauconite
Norrishite
KLiMn
3+
2
(Si
 
4
O
 
10
)O
 
2
Oellacherite
Oxykinoshitalite
(Ba,K)(Mg,Ti,Fe
3+
 
,Fe
2+
 
)
 
3
((Si,Al)
 
4
O
 
10
)(O,OH,F)
 
2
Oxyphlogopite
K(Mg,Ti,Fe)
 
3
[(Si,Al)
 
4
O
 
10
](O,F)
 
2
Phengite
Phlogopite
KMg
 
3
(AlSi
 
3
O
 
10
)(OH,F)
 
2
Polylithionite
KLi
 
2
Al(Si
 
4
O
 
10
)(F,OH)
 
2
Preiswerkite
NaMg
 
2
Al(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
Roscoelite
K(V
3+
 
,Al)
 
2
(AlSi
 
3
O
 
10
)(OH)
 
2
Shirokshinite
KNaMg
 
2
(Si
 
4
O
 
10
)F
 
2
Shirozulite
K(Mn
2+
 
,Mg)
 
3
(AlSi
 
3
O
 
10
)(OH)
 
2
Siderophyllite
KFe
2+
2
Al(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
Sokolovaite
CsLi
 
2
Al(Si
 
4
O
 
10
)F
 
2
Suhailite
(NH
 
4
)Fe
2+
3
(AlSi
 
3
O
 
10
)(OH)
 
2
Tainiolite
KLiMg
 
2
(Si
 
4
O
 
10
)F
 
2
Tetraferriphlogopite
KMg
 
3
(Fe
3+
 
Si
 
3
O
 
10
)(OH,F)
 
2
Tobelite
(NH
 
4
,K)Al
 
2
(AlSi
 
3
O
 
10
)(OH)
 
2
Trilithionite
K(Li,Al)
 
3
(AlSi
 
3
O
 
10
)(F,OH)
 
2
Voloshinite
Rb(LiAl
 
1.5
 
1.5
)(Al
 
0.5
Si
 
3.5
)O
 
10
F
 
2
Yangzhumingite
KMg
 
2.5
(Si
 
4
O
 
10
)F
 
2
Zinnwaldite
KLiFe
2+
 
Al(AlSi
 
3
O
 
10
)(F,OH)
 
2
Related Minerals - Strunz Grouping):

- +
8/H.13-10Wonesite
(Na,K)(Mg,Fe,Al)
 
6
((Al,Si)
 
4
O
 
10
)
 
2
(OH,F)
 
4
8/H.13-20Brammallite
(Na,H
 
3
O)(Al,Mg,Fe)
 
2
((Si,Al)
 
4
O
 
10
)(OH)
 
2
Related Minerals - Hey's Index Grouping:

- +
16.20.1Glaucophane
◻[Na
 
2
][Mg
 
3
Al
 
2
]Si
 
8
O
 
22
(OH)
 
2
16.20.2Sodium-anthophyllite
16.20.3Sodium Gedrite
16.20.4Crossite
16.20.5Ferro-eckermannite
NaNa
 
2
(Fe
2+
 
,
 
4
Al)Si
 
8
O
 
22
(OH)
 
2
16.20.6Wonesite
(Na,K)(Mg,Fe,Al)
 
6
((Al,Si)
 
4
O
 
10
)
 
2
(OH,F)
 
4
16.20.8Lennilenapeite
K
 
6-7
(Mg,Mn,Fe,Zn)
 
48
(Si,Al)
 
72
(O,OH)
 
216
· 16H
 
2
O
16.20.9Stilpnomelane
(K,Ca,Na)(Fe
2+
 
,Mg,Al,Fe
3+
 
)
 
8
(Si,Al)
 
12
(O,OH)
 
36
· nH
 
2
O
Related Minerals - Dana Grouping):

- +
71.2.2.1Muscovite
KAl
 
2
(AlSi
 
3
O
 
10
)(OH)
 
2
71.2.2.2Illite
K
 
0.65
Al
 
2.0
[Al
 
0.65
Si
 
3.35
O
 
10
](OH)
 
2
71.2.2.13Aspidolite
NaMg
 
3
(AlSi
 
3
O
 
10
)(OH)
 
2

Other Names for Glauconite

Synonyms:
GlaukonieGreensand
Other Languages:
Basque:Glaukonita
Dutch:Glauconiet
Esperanto:Glaŭkonito
French:Glauconite
German:Glaukonit
Glauconit
Hebrew:גלאוקוניט
Italian:Glauconite
Lithuanian:Glaukonitas
Polish:Glaukonit
Portuguese:Glauconita
Simplified Chinese:海绿石
Slovak:Glaukonit
Spanish:Glauconita
Swedish:Glaukonit
Ukrainian:Глауконіт
Varieties:
Aluminium-glauconiteMarsyatskiteSoda-Glauconite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Glauconite

Reference List:

- +
Schneider, H. (1927) A study of glauconite. Journal of Geology: 35: 289-310.
Hendricks, S.B. and Clarence S. Ross (1941), Chemical composition and genesis of glauconite and celadonite: American Mineralogist: 26: 683-708.
Bentor, Y. K. & Kestner, M. (1965): Mineralogy and origin of glauconite. Journal of Sedimentary Petrology 35, 155-166.
Foster, M. D. (1969), Studies of Celadonite and glauconite: USGS PP 614-F, 17 pp.
Slonimskaya, M. V., G. Besson, L. G. Daynyak, C. Tchoubar, and V. A. Drits (1986), The interpretation of the IR spectra of celadonites and glauconites in the region of OH-stretching frequencies: Clay Minerals: 21: 377-388.
Dainyak, L. G., and V. A. Drits (1987), Interpretation of Mössbauer spectra of nontronite, celadonite, and glauconite: Clays and Clay Minerals: 35: 363-372.
Sakharov, B. A., G. Besson, V. A. Drits, M. Y. Kameneva, A. L. Salyn, and B. B. Smoliar (1990), X-ray study of the nature of stacking faults in the structure of glauconites: Clay Minerals: 25: 419-435.
Dainyak, L. G., V. A. Drits, and L. M. Heifits (1992), Computer simulation of cation distribution in dioctahedral 2:1 layer silicates using IR-data: Application to Mössbauer spectroscopy of a glauconite sample: Clays and Clay Minerals: 40: 470-479.
Drits, V. A., L. G. Dainyak, F. Muller, G. Besson, and A. Manceau (1997a), Isomorphous cation distribution in celadonites, glauconites and Fe-illites determined by infrared, Mössbauer and EXAFS spectroscopy: Clay Minerals: 32: 153-180.
Gaines, Richard V., H. Catherine, W. Skinner, Eugene E. Foord, Brian Mason, Abraham Rosenzweig, and Vandall King (1997), Dana's New Mineralogy : The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana: p. 1453.
Rieder et.al. 1998, Nomenclature of the Micas: IMA Mica Subcommittee report, Canadian Mineralogist 36: 905-912.

Internet Links for Glauconite

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  • Localities for Glauconite

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