Magadiite
A valid IMA mineral species
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About Magadiite
Formula:
Na2Si14O29 · 11H2O
Colour:
White
Hardness:
2
Specific Gravity:
2.25 (Calculated)
Crystal System:
Orthorhombic
Name:
Named for the type locality Lake Magadi.
Type Locality:
This page provides mineralogical data about Magadiite.
Unique Identifiers
Mindat ID:
2530
Long-form identifier:
mindat:1:1:2530:6
GUID
(UUID V4):
(UUID V4):
f0531c94-04b8-440f-8364-4f273a4dcecd
IMA Classification of Magadiite
Approved
IMA Formula:
Na2Si14O28(OH)2 · 8H2O
First published:
1967
Classification of Magadiite
9.EA.20
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
78.7.12.1
78 : Unclassified Silicates
7 :
78 : Unclassified Silicates
7 :
14.1.5
14 : Silicates not Containing Aluminum
1 : Silicates of the alkali metals
14 : Silicates not Containing Aluminum
1 : Silicates of the alkali metals
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Mgd | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mgd | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261â264 doi:10.1180/clm.2020.30 |
Physical Properties of Magadiite
Transparency:
Translucent, Opaque
Colour:
White
Streak:
White
Hardness:
2 on Mohs scale
Comment:
Tenacity: Puttylike
Density:
2.25 g/cm3 (Calculated)
Optical Data of Magadiite
Type:
Biaxial
RI values:
nα = 1.470
Max Birefringence:
δ = 1.470
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
relatively weak
Chemistry of Magadiite
Mindat Formula:
Na2Si14O29 · 11H2O
Elements listed:
Common Impurities:
Ti,Al,Fe,Mn,Mg,Ca,K
Crystallography of Magadiite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Fdd2
Cell Parameters:
a = 10.5035(9) Å, b = 10.0262(9) Å, c = 61.9608(46) Å
Ratio:
a:b:c = 1.048 : 1 : 6.18
Unit Cell V:
6,525.10 Ă
Âł (Calculated from Unit Cell)
Morphology:
Putty-like laminae to very thin platy.
Comment:
Space Group: F2dd; Z undetermined
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0012231 | Magadiite | Garces J M, Rocke S C, Crowder C E, Hasha D L (1988) Hypothetical structures of magadiite and sodium octosilicate and structural relationships between the layered alkali metal silicates and the mordenite- and pentasil-group zeolites Clays and Clay Minerals 36 409-418 | 1988 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 15.41 Ă | (100) |
| 3.44 Ă | (80) |
| 3.146 Ă | (50) |
| 3.30 Ă | (35) |
| 5.18 Ă | (19) |
| 4.46 Ă | (18) |
| 5.01 Ă | (16) |
Comments:
Lake Magadi, Kenya. The data are from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earthâs earliest Hadean crust | >4.50 |
| 10 : Basalt-hosted zeolite minerals | |
| Stage 3b: Earthâs earliest hydrosphere | >4.45 |
| 14 : Hot springs, geysers, and other subaerial geothermal minerals | |
| 16 : Low-đ aqueous alteration of Hadean subaerial lithologies (see also #23) | |
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Magadiite
General Appearance of Type Material:
White putty-like laminae, in beds varying in thickness from 5 cm to 60 cm.
Place of Conservation of Type Material:
National School of Mines, Paris, France.
National Museum of Natural History, Washington, D.C., USA, 121336.
National Museum of Natural History, Washington, D.C., USA, 121336.
Geological Setting of Type Material:
Evaporite from saline brine.
Associated Minerals at Type Locality:
Reference:
Eugster, H.P. (1967) Hydrous sodium silicates from Lake Magadi, Kenya: Precursors of bedded chert. Science: 157: 1177-1180.
Synonyms of Magadiite
Other Language Names for Magadiite
Common Associates
Associated Minerals Based on Photo Data:
| 5 photos of Magadiite associated with Kenyaite | Na2Si22O41(OH)8 · 6H2O |
| 3 photos of Magadiite associated with Stishovite | SiO2 |
| 3 photos of Magadiite associated with Coesite | SiO2 |
| 3 photos of Magadiite associated with Microcline | K(AlSi3O8) |
| 2 photos of Magadiite associated with Varennesite | Na8Mn2Si10O25(OH,Cl)2 · 12H2O |
| 2 photos of Magadiite associated with Silhydrite | Si3O6 · H2O |
| 1 photo of Magadiite associated with Quartz | SiO2 |
| 1 photo of Magadiite associated with Pectolite | NaCa2Si3O8(OH) |
| 1 photo of Magadiite associated with Magnesio-arfvedsonite | {Na}{Na2}{Mg4Fe3+}(Si8O22)(OH)2 |
| 1 photo of Magadiite associated with Aegirine | NaFe3+Si2O6 |
Related Minerals - Strunz-mindat Grouping
| 9.EA. | Bussyite-(Y) | (Y,REE,Ca)3(Na,Ca)6MnSi9Be5(O,OH,F)34 |
| 9.EA. | Fluorapophyllite-(NHâ) | NH4Ca4(Si8O20)F · 8H2O |
| 9.EA. | Hydroxymcglassonite-(K) | KSr4Si8O20(OH) · 8H2O |
| 9.EA.05 | Cuprorivaite | CaCuSi4O10 |
| 9.EA.05 | Gillespite | BaFe2+Si4O10 |
| 9.EA.05 | Effenbergerite | BaCuSi4O10 |
| 9.EA.05 | Wesselsite | SrCuSi4O10 |
| 9.EA.07 | Fluorapophyllite-(Cs) | CsCa4(Si8O20)F · 8H2O |
| 9.EA.10 | Ekanite | Ca2ThSi8O20 |
| 9.EA.15 | Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O |
| 9.EA.15 | Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O |
| 9.EA.15 | Fluorapophyllite-(Na) | NaCa4(Si8O20)F · 8H2O |
| 9.EA.25 | Dalyite | K2ZrSi6O15 |
| 9.EA.25 | Davanite | K2TiSi6O15 |
| 9.EA.30 | Sazhinite-(Ce) | Na2CeSi6O14 · 6H2O |
| 9.EA.30 | Sazhinite-(La) | Na3La[Si6O15] · 2H2O |
| 9.EA.35 | Armstrongite | CaZr[Si6O15] · 3H2O |
| 9.EA.40 | Okenite | Ca10Si18O46 · 18H2O |
| 9.EA.45 | Nekoite | Ca3Si6O15 · 7H2O |
| 9.EA.45 | Perettiite-(Y) | Y2Mn4FeSi2B8O24 |
| 9.EA.45 | Badakhshanite-(Y) | Y2Mn4Al(Si2B7BeO24) |
| 9.EA.47 | Shlykovite | KCa[Si4O9(OH)] · 3H2O |
| 9.EA.50 | Cavansite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.50 | Diegogattaite | Na2CaCu2Si8O20 · H2O |
| 9.EA.52 | Yangite | PbMnSi3O8 · H2O |
| 9.EA.55 | Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.60 | Penkvilksite | Na4Ti2Si8O22 · 4H2O |
| 9.EA.60 | Tumchaite | Na2Zr(Si4O11) · 2H2O |
| 9.EA.65 | Nabesite | Na2BeSi4O10 · 4H2O |
| 9.EA.70 | Ajoite | (K,Na)Cu7AlSi9O24(OH)6 · 3H2O |
| 9.EA.75 | Zeravshanite | Na2Cs4Zr3[Si18O45]*2H2O |
| 9.EA.80 | Bussyite-(Ce) | (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 |
| 9.EA.85 | Plumbophyllite | Pb2Si4O10 · H2O |
Other Information
Notes:
Magadiite in dilute acid at room temperature produces a hydrous form of silica. Subsequent treatment of the silica with concentrated solutions of Na2CO3 or NaOH produces magadiite again.
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 Magadiite
mindat.org URL:
https://www.mindat.org/min-2530.html
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References for Magadiite
Localities for Magadiite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
Bolivia | |
| Abdelouas et al. (1995) |
Canada | |
| 166-175. +2 other references |
| HorvĂĄth et al. (1998) |
| HorvĂĄth et al. (1998) | |
Chad | |
| Clays and Clay Minerals. Vol. 35 | |
Kenya | |
| PĂ©rinet et al. (1982) |
| New data on minerals. M.: 2003. Volume ... +3 other references |
Namibia | |
| ... +1 other reference |
Niger | |
| Sebag et al. (2001) |
Russia | |
| webmineral.ru (n.d.) |
USA | |
| Van Nostrand Reinholt Press: 442. +2 other references |
| www.mineralsocal.org. +7 other references |
| Rooney et al. (1969) |
Quick NavTopAbout MagadiiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Lake Magadi, Kajiado County, Kenya