Loughlinite
A valid IMA mineral species
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About Loughlinite
Gerald Francis Loughlin
Formula:
Na2Mg3Si6O16 · 8H2O
Colour:
White
Lustre:
Silky, Pearly, Dull
Hardness:
1
Specific Gravity:
2.165
Crystal System:
Orthorhombic
Member of:
Name:
Named in honor of the late Dr. Gerald Francis Loughlin [December 11, 1880 Hyde Park, MA, USA - October 22, 1946], former Chief Geologist of the United States Geological Survey.
Typically found as fibrous white vein fillings in fractures in sodium-rich rocks.
Unique Identifiers
Mindat ID:
2441
Long-form identifier:
mindat:1:1:2441:5
IMA Classification of Loughlinite
Approved
IMA Formula:
Na2Mg3Si6O16·8H2O
First published:
1960
Classification of Loughlinite
9.EE.25
9 : SILICATES (Germanates)
E : Phyllosilicates
E : Single tetrahedral nets of 6-membered rings connected by octahedral nets or octahedral bands
9 : SILICATES (Germanates)
E : Phyllosilicates
E : Single tetrahedral nets of 6-membered rings connected by octahedral nets or octahedral bands
74.3.1b.3
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
14.4.12
14 : Silicates not Containing Aluminum
4 : Silicates of Mg
14 : Silicates not Containing Aluminum
4 : Silicates of Mg
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Lou | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Lou | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
| Lou | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Physical Properties of Loughlinite
Silky, Pearly, Dull
Transparency:
Translucent
Colour:
White
Streak:
White
Hardness:
1 on Mohs scale
Tenacity:
Flexible
Fracture:
Fibrous
Density:
2.165 g/cm3 (Measured) 2.22 g/cm3 (Calculated)
Optical Data of Loughlinite
Type:
Biaxial (+)
RI values:
nα = 1.500 nβ = 1.505 nγ = 1.525
2V:
Measured: 60° , Calculated: 54°
Birefringence:
0.025
Max. Birefringence:
δ = 0.025
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
relatively weak
Optical Extinction:
Parallel.
Chemistry of Loughlinite
Mindat Formula:
Na2Mg3Si6O16 · 8H2O
Element Weights:
Common Impurities:
Ti,Al,Fe
Crystallography of Loughlinite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 14.66 Å, b = 26.71 Å, c = 5.26 Å
Ratio:
a:b:c = 0.549 : 1 : 0.197
Unit Cell V:
2,059.65 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Fibrous aggregates, usually parallel.
Comment:
Space Group: Pncn:
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.8 Å | (100) |
| 7.60 Å | (30) |
| 4.80 Å | (50) |
| 4.45 Å | (100) |
| 3.79 Å | (100) |
| 3.65 Å | (100) |
| 2.90 Å | (70) |
Comments:
JCPDS 13-310
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
Type Occurrence of Loughlinite
General Appearance of Type Material:
Fibrous, to 1 cm; massive
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 117717
Geological Setting of Type Material:
Originally found in dolomitic shale.
Associated Minerals at Type Locality:
Other Language Names for Loughlinite
Relationship of Loughlinite to other Species
Member of:
Other Members of Sepiolite Group:
| Falcondoite | (Ni,Mg)4Si6O15(OH)2 · 6H2O | Orth. |
| Ferrisepiolite | (Fe3+,Fe2+,Mg)4((Si,Fe3+)6O15)(O,OH)2 · 6H2O | Orth. mmm(2/m2/m2/m) |
| Sepiolite | Mg4(Si6O15)(OH)2 · 6H2O | Orth. mmm(2/m2/m2/m) : Pnna |
Common Associates
Associations Based on Photo Data:
| 6 photos of Loughlinite associated with Searlesite | Na(H2BSi2O7) |
| 1 photo of Loughlinite associated with Shortite | Na2Ca2(CO3)3 |
| 1 photo of Loughlinite associated with Bradleyite | Na3Mg(CO3)(PO4) |
Related Minerals - Strunz-mindat Grouping
| 9.EE. | Cairncrossite | Sr2Ca7-xNa2x(Si4O10)4(OH)2(H2O)15-x |
| 9.EE.05 | Bementite | Mn7Si6O15(OH)8 |
| 9.EE.07 | Innsbruckite | Mn33(Si2O5)14(OH)38 |
| 9.EE.10 | 'Brokenhillite' | Mn8Si6O15(OH)10 |
| 9.EE.10 | Mcgillite | (Mn,Fe)8Si6O15(OH)8Cl2 |
| 9.EE.10 | Friedelite | Mn2+8Si6O15(OH,Cl)10 |
| 9.EE.10 | Pyrosmalite-(Mn) | Mn2+8Si6O15(OH,Cl)10 |
| 9.EE.10 | Pyrosmalite-(Fe) | Fe2+8Si6O15(OH,Cl)10 |
| 9.EE.15 | Nelenite | Mn2+16As3+3Si12O36(OH)17 |
| 9.EE.15 | Schallerite | Mn2+16As3Si12O36(OH)17 |
| 9.EE.20 | Palygorskite | ◻Al2Mg2◻2Si8O20(OH)2(H2O)4 · 4H2O |
| 9.EE.20 | Yofortierite | Mn2+Mn2+2Mn2+2◻2Si8O20(OH)2(H2O)4 · 4H2O |
| 9.EE.20 | Windhoekite | Fe3+(Fe3+1.67◻0.33)Ca2◻2Si8O20(OH)2(H2O)4(OH)2 · 6H2O |
| 9.EE.20 | Windmountainite | ◻Fe3+2Mg2◻2Si8O20(OH)2(H2O)4 · 4H2O |
| 9.EE.20 | Ikorskyite | KMn3+(Si4O10) · 3H2O |
| 9.EE.20 | Tuperssuatsiaite | Fe3+Fe3+2(Na◻)◻2Si8O20(OH)2(H2O)4 · 2H2O |
| 9.EE.20 | 'Unnamed (Na-Ca-Fe-Silicate-Hydrate)' | NaCa(Fe2+,Al,Mn)5[Si8O19(OH)](OH)7 · 5H2O |
| 9.EE.25 | Sepiolite | Mg4(Si6O15)(OH)2 · 6H2O |
| 9.EE.25 | Falcondoite | (Ni,Mg)4Si6O15(OH)2 · 6H2O |
| 9.EE.25 | Kalifersite | (K,Na)5Fe3+7Si20O50(OH)6 · 12H2O |
| 9.EE.30 | Orlymanite | Ca4Mn3Si8O20(OH)6 · 2H2O |
| 9.EE.30 | Tungusite | Ca4Fe2Si6O15(OH)6 |
| 9.EE.30 | Gyrolite | NaCa16Si23AlO60(OH)8 · 14H2O |
| 9.EE.35 | Reyerite | (Na,K)2Ca14(Si,Al)24O58(OH)8 · 6H2O |
| 9.EE.35 | Kodamaite | Na3(Ca5Na)Si16O36(OH)4F2 · (14-x)H2O |
| 9.EE.35 | Truscottite | (Ca,Mn)14Si24O58(OH)8 · 2H2O |
| 9.EE.40 | Natrosilite | Na2Si2O5 |
| 9.EE.45 | Makatite | Na2Si4O8(OH)2 · 4H2O |
| 9.EE.50 | Varennesite | Na8Mn2Si10O25(OH,Cl)2 · 12H2O |
| 9.EE.55 | Raite | Mn2+Mn2+2Na2(◻1.75Ti0.25)Si8O20(OH)2(H2O)4 · Na(H2O)6 |
| 9.EE.60 | Intersilite | Na6Mn2+Ti[Si10O24(OH)](OH)3 · 4H2O |
| 9.EE.65 | Zakharovite | Na4Mn5Si10O24(OH)6 · 6H2O |
| 9.EE.65 | Shafranovskite | Na3K2(Mn,Fe,Na)4[Si9(O,OH)27](OH)2 · nH2O |
| 9.EE.70 | Zeophyllite | Ca13Si10O28(OH)2F8 · 6H2O |
| 9.EE.75 | Minehillite | (K,Na)2-3Ca28Zn4Al4Si40O112(OH)16 |
| 9.EE.80 | Fedorite | (Na,K)2-3(Ca4Na3)Si16O38(OH,F)2 · 3.5H2O |
| 9.EE.80 | Martinite | (Na,◻,Ca)12Ca4(Si,S,B)14B2O38(OH,Cl)2F2 · 4H2O |
| 9.EE.80 | Ellingsenite | Na5Ca6Si18O38(OH)13 · 6H2O |
| 9.EE.85 | Lalondeite | (Na,Ca)6(Ca,Na)3Si16O38(F,OH)2 · 3H2O |
Fluorescence of Loughlinite
Not fluorescent.
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Loughlinite
mindat.org URL:
https://www.mindat.org/min-2441.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Loughlinite
Reference List:
Fahey, J. J., Ross, Malcolm, Axelrod, J. M. (1960) Loughlinite, a new hydrous sodium magnesium silicate. American Mineralogist, 45 (3-4) 270-281
(1962) International Mineralogical Association: Commission on New Minerals and Mineral Names. Mineralogical Magazine and Journal of the Mineralogical Society, 33 (258) 260-263 doi:10.1180/minmag.1962.033.258.09
Echle, Wolfram (1967) Loughlinit (Na-Sepiolith) und Analcim in neogenen Sedimenten Anatoliens. Contributions to Mineralogy and Petrology, 14 (2) 86-101 doi:10.1007/bf00377527
Kadir, S., Bas, H., Karakas, Z. (2002) Origin of sepiolite and loughlinite in a neogene volcano-sedimentary lacustrine environment, Mihaliccik-Eskisehir, Turkey. The Canadian Mineralogist, 40 (4) 1091-1102 doi:10.2113/gscanmin.40.4.1091
Localities for Loughlinite
Showing 14 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| ZHANG et al. (2018) |
Namibia | |
| Buch et al. (1996) |
Pacific Ocean | |
| Fryer et al. (1992) |
South Africa | |
| Roelofse (2010) |
| Roelofse (2010) |
Turkey | |
| Helvaci (1998) |
| Echle (1967) |
USA | |
| Tank (1972) +1 other reference | |
| Bullock (1981) |
| Williams (2017) |
| Milton (1977) |
| Fahey et al. (1960) +1 other reference |
| Fahey et al. (1960) | |
| Fahey et al. (1960) |
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Westvaco mine, Green River Basin, Sweetwater County, Wyoming, USA