Vote for your favorite mineral in #MinCup26! - Azurite vs. Smithsonite
It's carbonate-vs-carbonate to kick off Mineral Cup 2026 with copper-rich Azurite against zinc-rich Smithsonite.
Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic TimeExplore Fossils
Minerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral QuizTime Machine
Photo SearchPhoto GalleriesSearch by ColorPhoto Colour ExplorerNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Steedeite

A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
05607800017271972042858.jpg
Tony Steede
Formula:
NaMn2[Si3BO9](OH)2
Colour:
Colorless to pale pink; white
Lustre:
Sub-Vitreous, Silky
Specific Gravity:
3.106 (Calculated)
Crystal System:
Triclinic
Name:
Named in 2013 by M. M. Haring and Andrew M. McDonald in honor of Anthony Hosford Steede, dedicated mineral collector and specialist in the minerals of Mont Saint-Hilaire, Quebec, Canada.
Closely related to the sérandite-pectolite series of the pyroxenoid group and is the first mineral found to contain single loop-branched dreier silicate chains.

Non-hydrate counterpart of nolzeite.

Structurally similar to scheuchzerite and saneroite.



Hide all sections | Show all sections

Unique IdentifiersHide

Mindat ID:
41101
Long-form identifier:
mindat:1:1:41101:7

Similar NamesHide

SteatiteA variety of TalcMg3(Si4O10)(OH)2

IMA Classification of SteedeiteHide

IMA status:
Approved
IMA status notes:
Redefined by the IMA
Approval year:
2013
First published:
2014
Approval history:
A mineral with the name "steedeite" were originally published in the CNMNC Newsletter No 7 (2010) as IMA2010-049. This was later found to be identical to catapleiite and was discredited in CMNC Newsletter No 11 (2011). The current steedeite was approved published in CNMNC Newsletter No 17 (2013) and formally described by Haring et al. (2014)
Type description reference:
Haring, M. M. M., McDonald, A. M. (2014) Steedeite, NaMn2[Si3BO9](OH)2: characterization, crystal-structure determination, and origin. The Canadian Mineralogist, 52 (1) 47-60 doi:10.3749/canmin.52.1.47

Classification of SteedeiteHide

Strunz-mindat (2026):
9.DG.02

9 : SILICATES (Germanates)
D : Inosilicates
G : Inosilicates with 3-periodic single and multiple chains

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
SedIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of SteedeiteHide

Lustre:
Sub-Vitreous, Silky
Transparency:
Transparent, Translucent
Colour:
Colorless to pale pink; white
Streak:
White
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Density:
3.106 g/cm3 (Calculated)

Optical Data of SteedeiteHide

Type:
Biaxial

Chemistry of SteedeiteHide

Mindat Formula:
NaMn2[Si3BO9](OH)2
Element Weights:
Element% weight
O43.354 %
Mn27.067 %
Si20.756 %
Na5.663 %
B2.663 %
H0.497 %

Calculated from ideal end-member formula.
Elements listed:
B, H, Mn, Na, O, Si - search for minerals with similar chemistry

Crystallography of SteedeiteHide

Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Setting:
P1
Cell Parameters:
a = 6.837(1) Å, b = 7.575(2) Å, c = 8.841(2) Å
α = 99.91(3)°, β = 102.19(3)°, γ = 102.78 (2)°
Ratio:
a:b:c = 0.903 : 1 : 1.167
Unit Cell V:
424.81 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Acicular crystals.

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File    Best | x | y | z | a | b | c
Rotation
Stop | Start
Labels
Console Off | On | Grey | Yellow
IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0020229SteedeiteHaring M M M, McDonald A M (2014) Steedeite, NaMn2[Si3BO9](OH)2: characterization, crystal-structure determination, and origin The Canadian Mineralogist 52 47-602014Poudrette quarry, Monteregie, Quebec, Canada0293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4b: Highly evolved igneous rocks>3.0
35 : Ultra-alkali and agpaitic igneous rocks

Type Occurrence of SteedeiteHide

Type Locality:
ⓘ Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada
General Appearance of Type Material:
Bundles of slightly radiating acicular crystals to 0.5 mm.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Royal Ontario Museum, Queen’s Park, Toronto, Ontario, Canada, catalogue number M56489
Geological Setting of Type Material:
Late-stage mineral in sodalite syenite
Associated Minerals at Type Locality:
AegirineAnalcimeCatapleiiteEudialyte GroupMicrocline
NatroliteSeranditeSodaliteThermonatrite
Reference:
Haring, M. M. M., McDonald, A. M. (2014) Steedeite, NaMn2[Si3BO9](OH)2: characterization, crystal-structure determination, and origin. The Canadian Mineralogist, 52 (1) 47-60 doi:10.3749/canmin.52.1.47

Synonyms of SteedeiteHide

Other Language Names for SteedeiteHide

Dutch:Steedeiet
German:Steedeit

Related Minerals - Strunz-mindat GroupingHide

9.DG.Barrydawsonite-(Y)Na1.5Y0.5CaSi3O8(OH)Mon. 2/m : P21/b
9.DG.ParatobermoriteCa5AlSi5O16(OH) · 5H2OMon. 2/m
9.DG.CalcinaksiteKNaCa(Si4O10) · H2OTric. 1 : P1
9.DG.AlvesiteNaKZrSi6O15 · 2H2OOrth. mmm (2/m 2/m 2/m)
9.DG.02NolzeiteNaMn2[Si3BO9](OH)2 · 2H2OTric. 1 : P1
9.DG.05MurakamiiteLiCa2Si3O8(OH)Tric. 1 : P1
9.DG.05SeranditeNaMn2+2Si3O8(OH)Tric. 1 : P1
9.DG.05BustamiteCaMn2+(Si2O6)Tric. 1 : P1
9.DG.05PectoliteNaCa2Si3O8(OH)Tric. 1 : P1
9.DG.05TanohataiteLiMn2Si3O8(OH)Tric. 1 : P1
9.DG.05DalnegorskiteCa5Mn(Si3O9)2Tric. 1 : P1
9.DG.05'Wollastonite-1A'CaSiO3Tric. 1 : P1
9.DG.05WollastoniteCa3(Si3O9)Tric. 1 : P1
9.DG.05FerrobustamiteCaFe2+(Si2O6)Tric. 1
9.DG.05SchizoliteNaCaMnSi3O8(OH)Tric. 1 : P1
9.DG.07CascanditeCaScSi3O8(OH)Tric. 1
9.DG.08PlombièriteCa5Si6O16(OH)2 · 7H2OOrth.
9.DG.10ClinotobermoriteCa5Si6O17 · 5H2OMon.
9.DG.10RiversideiteCa5Si6O16(OH)2 · 2H2O Orth.
9.DG.10TobermoriteCa5Si6O17 · 5H2OMon. 2 : P21
9.DG.12JusiteNa2Ca15Al4Si16O54 · 17H2O
9.DG.12KenotobermoriteCa4Si6O15(OH)2 · 5H2OMon.
9.DG.15FoshagiteCa4(Si3O9)(OH)2Tric. 1 : P1
9.DG.20JenniteCa9(Si3O9)2(OH)8 · 8H2OTric. 1 : P1
9.DG.20KameneviteK2TiSi3O9 · H2OOrth. 2 2 2 : P21 21 21
9.DG.25ParaumbiteK3Zr2H(Si3O9)2 · nH2OOrth. mm2
9.DG.25UmbiteK2(Zr,Ti)Si3O9 · H2OOrth. 2 2 2 : P21 21 21
9.DG.30SørenseniteNa4SnBe2Si6O16(OH)4Mon. 2/m : B2/b
9.DG.32Escheite Ca2NaMnTi5[Si12O34]O2(OH)3 · 12H2OOrth. mm2 : Ama2
9.DG.35XonotliteCa6(Si6O17)(OH)2Mon. 2/m : B2/m
9.DG.40HillebranditeCa2(SiO3)(OH)2Orth. mmm (2/m 2/m 2/m) : Cmcm
9.DG.45ZoriteNa8(Ti,Nb)5(Si6O17)2(OH,O)5 · 14H2OOrth.
9.DG.45ChivruaiiteCa4(Ti,Nb)5(Si6O17)2(OH,O)5 · 13-14H2OOrth. mmm (2/m 2/m 2/m) : Cmmm
9.DG.50Haineaultite(Na,Ca)5Ca(Ti,Nb)5(Si6O17)2(OH,F)8 · 5H2OOrth. 2 2 2 : C2 2 2
9.DG.55EpididymiteNa2Be2Si6O15 · H2OOrth. mmm (2/m 2/m 2/m) : Pnma
9.DG.60EudidymiteNa2Be2Si6O15 · H2OMon. 2/m : B2/b
9.DG.65ElpiditeNa2ZrSi6O15 · 3H2OOrth.
9.DG.65PatyniteNaKCa4[Si9O23]Tric. 1 : P1
9.DG.67WhelaniteCu2+2Ca6[Si6O17(OH)](CO3)(OH)3 · 2H2OOrth. mm2 : Pnn2
9.DG.70EnricofrancoiteKNaCaSi4O10Tric. 1 : P1
9.DG.70YusupoviteNa2Zr(Si6O15) · 2.5H2OMon. 2/m : B2/m
9.DG.70LitidioniteKNaCuSi4O10Tric. 1 : P1
9.DG.70Fenaksite(K,Na)4(Fe,Mn)2(Si4O10)2(OH,F)Tric. 1 : P1
9.DG.70ManaksiteKNaMnSi4O10Tric. 1 : P1
9.DG.75SenkevichiteCsKNaCa2TiO[Si7O18](OH)Tric. 1 : P1
9.DG.75TinaksiteK2Na(Ca,Mn2+)2TiO[Si7O18(OH)]Tric.
9.DG.75TokkoiteK2Ca4[Si7O18(OH)](OH,F)Tric.
9.DG.80FluorcanasiteK3Na3Ca5Si12O30F4 · H2OMon. m : Bm
9.DG.80CanasiteK3Na3Ca5Si12O30(OH)4Mon. m : Bm
9.DG.85MiseriteK1.5-x(Ca,Y,REE)5(Si6O15)(Si2O7)(OH,F)2 · yH2OTric.
9.DG.90FrankameniteK3Na3Ca5(Si12O30)(F,OH)4 · H2OTric. 1 : P1
9.DG.92Charoite(K,Sr)15-16(Ca,Na)32[Si6O11(O,OH)6]2[Si12O18(O,OH)12]2[Si17O25(O,OH)18]2(OH,F)4 · ~3H2OMon. 2/m : P21/m
9.DG.95YuksporiteK4(Ca,Na)14(Sr,Ba)2(◻,Mn,Fe)(Ti,Nb)4(O,OH)4(Si6O17)2(Si2O7)3(H2O,OH)3Mon. 2/m : P21/m
9.DG.97Eveslogite(Na,K,Ca,Sr,Ba)48 [(Ti,Nb,Mn,Fe2+)12Si48O144(OH)12](F,OH,Cl)14Mon. 2/m : P2/m

Fluorescence of SteedeiteHide

In UV light:
Weak pale green to pale yellow fluorescence under medium-wave radiation

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.

Internet Links for SteedeiteHide

References for SteedeiteHide

Localities for SteedeiteHide

Showing 1 localities.

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.
Hide all sections | Show all sections

Locality ListHide

- 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). 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 (e.g. 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
Williams et al. (2011) +2 other references
Quick NavTopUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
 
and/or  
Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 1, 2026 11:14:14 Page updated: May 4, 2026 23:38:14
Go to top of page