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Mn5Si8O20(OH)2 · 8-9H2O
Pink to pale violet, brown
Silky, Dull
Specific Gravity:
Crystal System:
Named in honor of Yves Oscar Fortier (1914-2014), Director of the Geological Survey of Canada (1964-1973), for his many contributions to Canadian geosciences.
Compare 'UM1969-14-SiO:FeHMn' - reported from the same environment.

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Classification of YofortieriteHide

Approval Year:

9 : SILICATES (Germanates)
E : Phyllosilicates
E : Single tetrahedral nets of 6-membered rings connected by octahedral nets or octahedral bands

74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips

14 : Silicates not Containing Aluminum
17 : Silicates of Mn

Physical Properties of YofortieriteHide

Silky, Dull
Pink to pale violet, brown
2½ on Mohs scale
2.18 g/cm3 (Measured)    

Optical Data of YofortieriteHide

RI values:
nα = 1.530 nγ = 1.559
Max Birefringence:
δ = 0.029
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of YofortieriteHide

Mn5Si8O20(OH)2 · 8-9H2O
IMA Formula:
(Mn2+,Mg,Fe3+)5Si8O20(OH,H2O)2 · 7H2O
Common Impurities:

Crystallography of YofortieriteHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 14.1686 Å, b = 17.8583 Å, c = 5.2919 Å
β = 105.878°
a:b:c = 0.793 : 1 : 0.296
Unit Cell V:
1287.9 ų
Radiating fibres, single crystals are thin, about 1 micron.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
10.5 (100)
3.302 (90)
2.621 (30)
2.510 (20)
4.14 (18)
From type description, most important peaks

Type Occurrence of YofortieriteHide

Synonyms of YofortieriteHide

Other Language Names for YofortieriteHide

Simplified Chinese:锰坡缕石
Traditional Chinese:錳坡縷石

Relationship of Yofortierite to other SpeciesHide

Other Members of this group:
Palygorskite(Mg,Al)5(Si,Al)8O20(OH)2 · 8H2OMon. 2/m : B2/m
TuperssuatsiaiteNa2Fe3Si8O20(OH)2 · 4H2OMon. 2/m : B2/m
Unnamed (Na-Ca-Fe-Silicate-Hydrate)NaCa(Fe2+,Al,Mn)5[Si8O19(OH)](OH)7 · 5H2OTric. 1 : P1
WindhoekiteCa2Fe3+2.67[Si8O20](OH)4 · 10H2O Mon. 2/m : B2/m

Common AssociatesHide

Associated Minerals Based on Photo Data:
Microcline21 photos of Yofortierite associated with Microcline on
Analcime10 photos of Yofortierite associated with Analcime on
Aegirine7 photos of Yofortierite associated with Aegirine on
Eudialyte Group6 photos of Yofortierite associated with Eudialyte Group on
Serandite6 photos of Yofortierite associated with Serandite on
Eudialyte4 photos of Yofortierite associated with Eudialyte on
Smectite Group4 photos of Yofortierite associated with Smectite Group on
Natrolite4 photos of Yofortierite associated with Natrolite on
Varennesite3 photos of Yofortierite associated with Varennesite on
Orthojoaquinite-(La)2 photos of Yofortierite associated with Orthojoaquinite-(La) on

Related Minerals - Nickel-Strunz GroupingHide

9.EE.10BrokenhilliteMn8Si6O15(OH)10Hex. 6mm : P63mc
9.EE.10Pyrosmalite-(Fe)Fe2+8Si6O15(OH,Cl)10Trig. 3m (3 2/m) : P3m1
9.EE.10FriedeliteMn2+8Si6O15(OH,Cl)10Mon. 2/m : B2/m
9.EE.10Mcgillite(Mn,Fe)8Si6O15(OH)8Cl2Mon. 2/m : B2/m
9.EE.15SchalleriteMn2+16As3Si12O36(OH)17Trig. 3m : P3m1
9.EE.20Palygorskite(Mg,Al)5(Si,Al)8O20(OH)2 · 8H2OMon. 2/m : B2/m
9.EE.20TuperssuatsiaiteNa2Fe3Si8O20(OH)2 · 4H2OMon. 2/m : B2/m
9.EE.20WindhoekiteCa2Fe3+2.67[Si8O20](OH)4 · 10H2O Mon. 2/m : B2/m
9.EE.25Falcondoite(Ni,Mg)4Si6O15(OH)2 · 6H2OOrth.
9.EE.25LoughliniteNa2Mg3Si6O16 · 8H2OOrth.
9.EE.25SepioliteMg4(Si6O15)(OH)2 · 6H2OOrth. mmm (2/m 2/m 2/m) : Pnna
9.EE.25Kalifersite(K,Na)5Fe3+7Si20O50(OH)6 · 12H2OTric.
9.EE.30GyroliteNaCa16Si23AlO60(OH)8 · 14H2OTric.
9.EE.30OrlymaniteCa4Mn3Si8O20(OH)6 · 2H2OHex.
9.EE.35Reyerite(Na,K)2Ca14(Si,Al)24O58(OH)8 · 6H2OTrig.
9.EE.35Truscottite(Ca,Mn)14Si24O58(OH)8 · 2H2OTrig.
9.EE.45MakatiteNa2Si4O8(OH)2 · 4H2OMon. 2/m : P21/b
9.EE.50VarennesiteNa8Mn2Si10O25(OH,Cl)2 · 12H2OOrth.
9.EE.55RaiteNa4Mn2+3Ti0.25Si8O20(OH)2 · 10H2OOrth. 2 2 2 : C2 2 2
9.EE.60IntersiliteNa6Mn2+Ti[Si10O24(OH)](OH)3 · 4H2OMon.
9.EE.65Shafranovskite(Na,K)6(Mn,Fe)3Si9O24 · 6H2OTrig.
9.EE.65ZakharoviteNa4Mn5Si10O24(OH)6 · 6H2OTrig.
9.EE.70ZeophylliteCa13Si10O28(OH)2F8 · 6H2OTrig. 3 : R3
9.EE.80Fedorite(Na,K)2-3(Ca4Na3)Si16O38(OH,F)2 · 3.5H2OTric. 1 : P1
9.EE.80Martinite(Na,◻,Ca)12Ca4(Si,S,B)14B2O38(OH,Cl)2F2·4H2OTric. 1 : P1
9.EE.85Lalondeite(Na,Ca)6(Ca,Na)3Si16O38(F,OH)2·3H2OTric. 1 : P1

Related Minerals - Dana Grouping (8th Ed.)Hide

74.3.1a.1Palygorskite(Mg,Al)5(Si,Al)8O20(OH)2 · 8H2OMon. 2/m : B2/m
74.3.1a.2TuperssuatsiaiteNa2Fe3Si8O20(OH)2 · 4H2OMon. 2/m : B2/m

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

14.17.1RhodoniteMn2+SiO3Tric. 1
14.17.2TephroiteMn2+2SiO4Orth. mmm (2/m 2/m 2/m)
14.17.3BrauniteMn2+Mn3+6(SiO4)O8Tet. 4/mmm (4/m 2/m 2/m) : I41/acd
14.17.4AlleghanyiteMn2+5(SiO4)2(OH)2Mon. 2/m : P21/b
14.17.6LeucophoeniciteMn2+7(SiO4)3(OH)2Mon. 2/m : P21/b
14.17.7JerrygibbsiteMn2+9(SiO4)4(OH)2Orth. mmm (2/m 2/m 2/m) : Pbcn
14.17.9Parsettensite(K,Na,Ca)7.5(Mn,Mg)49Si72O168(OH)50 · nH2OMon. 2/m : B2/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 YofortieriteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Perrault, G., Harvey, Y., and Pertsowsky, R (1975) La yofortierite, un nouveau silicate hydraté de manganése de St Hilaire, P.Q. Canadian Mineralogist. 13: 68-74. (in French with English abstract). Abstracted in American Mineralogist (1976), 61, 341.
Horváth, L. Pfenninger-Horváth, E., Gault, R. A. & Tarassoff, P. (1998) Mineralogy of the Saint Amable sill, Varennes and Saint Amable, Québec, Canada. Mineralogical Record. 29:, 83-118.
Hawthorne, F.C., Abdu, Y.A., Tait, K.T. and Back, M.E. (2013): The crystal structure of yofortierite. Canadian Mineralogist. 51: 243-251.

Internet Links for YofortieriteHide

Localities for YofortieriteHide

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.
Canada (TL)
  • Québec
    • Montérégie
      • La Vallée-du-Richelieu RCM
        • Mont Saint-Hilaire
Perrault G., Harvey Y. and Pertsowsky R. (1975), La yofortierite, un nouveau silicate hydrate de manganese de St. Hilaire, P.Q. Canadian Mineralogist, 13, 68-74; HORVÁTH, L., and GAULT, R.G. (1990) The mineralogy of Mont Saint Hilaire. Mineralogical Record, 21, 284 359; Hawthorne, F.C., Abdu, Y.A., Tait, K.T. and Back, M.E. (2013): The crystal structure of yofortierite. Can. Mineral. 51, 243-251.
      • 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.
  • Kujalleq
    • Narsaq
Semenov, E. (2001): Notes on Ephesite, Terskite, Na-Komarovite, Ceriopyrochlore-(Ce), Joaquinite-(Ce) and other minerals from the Ilimaussaq alkaline complex, South Greenland, Geology of Greenland Survey Bulletin 190, 123-125; Petersen, O.V. (2001): List of all minerals identified in the Ilímaussaq alkaline complex, South Greenland. Geology of Greenland Survey Bulletin. 190, 25-33
        • Kuannersuit Plateau (Kvanefjeld)
Pavel M. Kartashov analytical data
  • Khomas Region
    • Windhoek District
      • Aris
Yakovenchuk, V.N., Ivanyuk, G.Yu., Pakhomovsky, Y.A., Selivanova, E.A., Mikhailova, J.A., Krivovichev, S.V., Zolotarev, A.A. and Zalkind, O.A. (2011): Ellingsenite, Na5Ca6Si18O38(OH)13·6H2O, a new martinite-related mineral from phonolite of the Aris alkaline complex (Namibia). Canadian Mineralogist, 49, 1165-1173.[listed as associated mineral, no details given]
  • Northern Region
    • Murmanskaya Oblast'
      • Lovozero Massif
Arzamastsev, A., Yakovenchuk, V., Pakhomovsky, Y., & Ivanyuk, G. (2008). The Khibina and Lovozero alkaline massifs: Geology and unique mineralization. In Guidbook for 33rd International Geological Congress Excursion (No. 47, p. 58).
P.M. Kartashov data; New Data on Minerals M., 2004 Vol 39 pp 5-13; Pekov, I. V., Chukanov, N. V., Yamnova, N. A., Zadov, A. E., & Tarassoff, P. (2007). Gjerdingenite-Na and gjerdingenite-Ca, two new mineral species of the labuntsovite group. The Canadian Mineralogist, 45(3), 529-539
Reiner Mielke 2016
  • Arkansas
    • Hot Spring Co.
      • Magnet Cove
Henry Barwood - unpublished (2010)
  • New Mexico
    • Otero Co.
      • Cornudas Mts
Michael C Michayluk Collection
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