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About MagadiiteHide

Na2Si14O29 · 11H2O
Crystal System:
Named for the type locality Lake Magadi.
This page provides mineralogical data about Magadiite.

Classification of MagadiiteHide


9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings

78 : Unclassified Silicates
7 :

14 : Silicates not Containing Aluminum
1 : Silicates of the alkali metals

Physical Properties of MagadiiteHide


Optical Data of MagadiiteHide

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.
Surface Relief:
relatively weak

Chemical Properties of MagadiiteHide

Na2Si14O29 · 11H2O
Common Impurities:

Crystallography of MagadiiteHide

Crystal System:
Cell Parameters:
a = 7.25 Å, b = 7.25 Å, c = 15.69 Å
β = 96.8°
a:b:c = 1 : 1 : 2.164
Unit Cell V:
818.90 ų (Calculated from Unit Cell)

Type Occurrence of MagadiiteHide

Synonyms of MagadiiteHide

Other Language Names for MagadiiteHide


Common AssociatesHide

Associated Minerals Based on Photo Data:
Chert4 photos of Magadiite associated with Chert on mindat.org.
Stishovite3 photos of Magadiite associated with Stishovite on mindat.org.
Kenyaite3 photos of Magadiite associated with Kenyaite on mindat.org.
Coesite3 photos of Magadiite associated with Coesite on mindat.org.
Varennesite2 photos of Magadiite associated with Varennesite on mindat.org.
Quartz1 photo of Magadiite associated with Quartz on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.EA.05CuprorivaiteCaCuSi4O10Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc
9.EA.05EffenbergeriteBaCuSi4O10Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc
9.EA.10EkaniteCa2ThSi8O20Tet. 4 2 2 : I4 2 2
9.EA.15Fluorapophyllite-(K)KCa4(Si8O20)(F,OH) · 8H2OTet. 4/mmm (4/m 2/m 2/m) : P4/mnc
9.EA.15Hydroxyapophyllite-(K)KCa4(Si8O20)(OH,F) · 8H2OTet.
9.EA.15Fluorapophyllite-(Na)NaCa4(Si8O20)F · 8H2OOrth.
9.EA.30Sazhinite-(La)Na3La[Si6O15] · 2H2OOrth. mm2 : Pmm2
9.EA.35ArmstrongiteCaZr[Si6O15] · 3H2OMon.
9.EA.40OkeniteCa10Si18O46 · 18H2OTric. 1 : P1
9.EA.45NekoiteCa3Si6O15·7H2OTric. 1 : P1
9.EA.50CavansiteCa(VO)Si4O10 · 4H2OOrth. mmm (2/m 2/m 2/m)
9.EA.55PentagoniteCa(VO)Si4O10 · 4H2OOrth. mm2
9.EA.60PenkvilksiteNa4Ti2Si8O22 · 4H2OOrth. mmm (2/m 2/m 2/m) : Pbcn
9.EA.60TumchaiteNa2Zr(Si4O11) · 2H2OMon.
9.EA.65NabesiteNa2BeSi4O10 · 4H2OOrth. 2 2 2 : P21 21 21
9.EA.70Ajoite(K,Na)Cu7AlSi9O24(OH)6 · 3H2OTric.
9.EA.75ZeravshaniteNa2Cs4Zr3[Si18O45]*2H2OMon. 2/m : B2/b
9.EA.80Bussyite-(Ce)(Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4Mon. 2/m : B2/b
9.EA.85PlumbophyllitePb2Si4O10 · H2OOrth. mmm (2/m 2/m 2/m) : Pbcn

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

14.1.3RevditeNa16Si16O27(OH)26 · 28H2OMon. 2 : B2
14.1.4MakatiteNa2Si4O8(OH)2 · 4H2OMon. 2/m : P21/b
14.1.6KenyaiteNa2Si22O41(OH)8 · 6H2OMon.
14.1.7GrumantiteNa(HSi2O5) · H2OOrth. mm2 : Fdd2
14.1.8SilinaiteNaLiSi2O5 · 2H2OMon. 2/m

Other InformationHide

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

References for MagadiiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Eugster H P (1967) Hydrous sodium silicates from Lake Magadi, Kenya: Precursors of bedded chert, Science, 157, 1177-1180.
McAtee J L, House R, Eugster H P (1968) Magadiite from Trinity County, California, American Mineralogist, 53, 2061-2069.
Bricker, O.P. (1969), Stability constants and Gibbs free energies of formation of magadiite and kenyaite: American Mineralogist: 54: 1026-1033.
Brindley, G.W. (1969), Unit cell of magadiite in air, in vacuo, and under other conditions: American Mineralogist: 54: 1583-1591.
Lagaly, G., K. Beneke & A. Weiss (1975), Magadiite and H-Magadiite 1. Sodium magadiite and some of its derivatives: American Mineralogist: 60: 642-649.
HORVÁTH, L., and GAULT, R.G. (1990) The mineralogy of Mont Saint Hilaire. Mineralogical Record, 21, 284 359.
HORVÁTH, L., PFENNINGER HORVÁTH, E., GAULT, R.A., and TARASSOFF, P. (1998) Mineralogy of the Saint Amable sill, Varennes and Saint Amable, Québec, Canada. Mineralogical Record, 29, 83 118.

Internet Links for MagadiiteHide

Localities for MagadiiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Potosí
    • Nor Lípez Province
      • San Juan
Abdelouas, A., Crovisier, J. L., Lutze, W., Ullman, W. J., & Risacher, F. (1995). Occurrence of silhydrite in a soda lake on the Bolivian Altiplano. Clay Minerals, 30(1), 77-82.
  • Québec
    • Montérégie
      • La Vallée-du-Richelieu RCM
        • Mont Saint-Hilaire
Horváth, L and Gault, R.A. (1990), The mineralogy of Mont Saint-Hilaire Quebec. Mineralogical Record: 21: 284-359.
      • Lajemmerais RCM
        • Varennes & St-Amable
HORVÁTH, L., PFENNINGER HORVÁTH, E., GAULT, R.A., and TARASSOFF, P. (1998) Mineralogy of the Saint Amable sill, Varennes and Saint Amable, Québec, Canada. Mineralogical Record, 29, 83 118.
Horváth, L., Pfenninger-Horváth, E., Gault, R. A., & Tarassoff, P. (1998): Mineralogy of the Saint-Amable Sill, Varennes and Saint-Amable, Québec. Mineralogical Record, 29: 83-118.
Clays and Clay Minerals. Vol. 35, No. 4, 318-320, 1987.
  • Baringo County
G. Périnet, J.J. Tiercelin, C.E. Barton : "Présence de kanémite dans les sédiments récents du lac Bogoria, Rift Gregory, Kenya", Bull. Minéral., 1982, 105, 633-639.
  • Kajiado County
McAtee, J.L., House, R., Eugster, H.P. (1968) Magadiite from Trinity County, California. The American Mineralogist, 53, 2061-2069. HB2/2 (1995). New data on minerals. M.: 2003. Volume 38 pp113.
  • Khomas Region
    • Windhoek District
      • Aris
Wartha, R., Palfi, A., Niedermayr, G., Brandstätter, F. and Petersen, O. V. (2001): Der Aris-Phonolith-Komplex und seine Mineralien. In Bahmann, U. and A. (Eds.), Namibia – Zauberwelt edler Steine und Kristalle, Bode-Verlag, Haltern, Germany, pp. 172-179. (in German); [http://www.koeln.netsurf.de/~w.steffens/aris.htm]
  • Orenburg Oblast
    • Adamovsky District
  • California
    • Inyo Co.
Bricker, O.P. (1969), Stability constants and Gibbs free energies of formation of magadiite and kenyaite: American Mineralogist: 54: 1032-1033; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 442.
    • Trinity Co.
      • Klamath Mts
        • Trinity Mts
          • Halls Gulch District
            • Wildcat Peak
Eugster, H.P., F.J. Blair, and R.A. Sheppard (1967) New hydrous sodium silicates from Kenya, Oregon and California. Geological Society of America Abstract with Program, 60.; McAtee, J.L., House, R., and Eugster, H.P. (1968) Magadiite from Trinity County, California. American Mineralogist: 53: 2061-2069; Barnes, I., J.B. Rapp & J.R. O’Neil (1972), Metamorphic assemblages and the direction of flow of metamorphic fluids in four instances of serpentinization: Contributions to Mineralogy and Petrology: 35: 264; Gude, A.J. and Sheppard, R.A. (1972) Silhydrite, 3SiO2 •H2O, a new mineral from Trinity County, California. American Mineralogist: 57: 1053-1065; American Mineralogist (1975): 60: 642-649; www.mineralsocal.org.; Gude A J, Sheppard R A (1972) Silhydrite, 3SiO2·H2O, a new mineral from Trinity County, California. American Mineralogist 57, 1053-1065; Lukasz Kruszewski specimen.
  • Oregon
    • Lake Co.
Am. Min. 54:1034
Mineral and/or Locality  
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