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Steacyite

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Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville RCM, Montérégie, Québec, Canada
© JBS 2006

Show Steacyite Photos (38)
Formula:
([ ],K)(Na,Ca)
 
2
(Th,U)[Si
 
8
O
 
20
]
System:TetragonalColour:Gray, dark brown, green, ...
Hardness:5
Name:Named after Harold Robert Steacy (b. 1923), mineralogist and curator, National Mineral Collection, Geological Survey of Canada.
This page provides mineralogical data about Steacyite.

Classification of Steacyite

IMA status:Approved 1981
Strunz 8th edition ID:8/E.10-30
Nickel-Strunz 10th (pending) edition ID:9.CH.10

9 : SILICATES (Germanates)
C : Cyclosilicates
H : [Si4O12]8- 4-membered double rings
Dana 8th edition ID:63.1.1.1

63 : CYCLOSILICATES Condensed Rings
1 : Condensed Rings (Steacyite group)
Hey's CIM Ref.:14.16.15

14 : Silicates not Containing Aluminum
16 : Silicates of U
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Type Occurrence of Steacyite

Type Locality:Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville RCM, Montérégie, Québec, Canada
Year of Discovery:1982

Physical Properties of Steacyite

Lustre:Vitreous, Greasy, Dull
Diaphaneity (Transparency):Translucent, Opaque
Colour:Gray, dark brown, green, beige
Hardness (Mohs):5

Crystallography of Steacyite

Crystal System:Tetragonal
Cell Parameters:a = 7.58Å, c = 14.76Å
Ratio:a:c = 1 : 1.947
Unit Cell Volume:V 848.06 ų (Calculated from Unit Cell)

Optical Data of Steacyite

Type:Uniaxial (-)
RI values: nω = 1.573 nε = 1.572
Maximum Birefringence:δ = 0.001

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low

Chemical Properties of Steacyite

Formula:
([ ],K)(Na,Ca)
 
2
(Th,U)[Si
 
8
O
 
20
]
Essential elements:K, Na, O, Si, Th
All elements listed in formula:Ca, K, Na, O, Si, Th, U
Common Impurities:As,Mn,Pb,F,P

Relationship of Steacyite to other Species

Member of Group:
Steacyite Group:
Related Minerals - Nickel-Strunz Grouping):

- +
9.CH.05Hyalotekite
(Ba,Pb,Ca,K)
 
6
(B,Si,Al)
 
2
(Si,Be)
 
10
O
 
28
(F,Cl)
9.CH.05Kapitsaite-(Y)
(Ba,K,Pb)
 
4
(Y,Ca)
 
2
Si
 
8
(B,Si)
 
4
O
 
28
F
9.CH.10Iraqite-(La)
K(Ca,Na)
 
2
(La,Ce,Th)[(Si,Al)
 
8
O
 
20
]
9.CH.10Turkestanite
(K,[ ])(Ca,Na)
 
2
(Th,U)[Si
 
8
O
 
20
] · nH
 
2
O
9.CH.10Arapovite
(K,[ ])(Ca,Na)
 
2
(U,Th)[Si
 
8
O
 
20
] · H
 
2
O
Related Minerals - Hey's Index Grouping:

- +
14.16.1Uranosilite
UO
 
3
 · 7SiO
 
2
14.16.2Coffinite
(U,Th)[(OH)
 
4x
|(SiO
 
4
)
 
1-x
]
14.16.3Soddyite
(UO
 
2
)
 
2
SiO
 
4
·2H
 
2
O
14.16.4Swamboite
UH
 
6
(UO
 
2
)
 
6
(SiO
 
4
)
 
6
·30H
 
2
O
14.16.5Weeksite
K
 
2
(UO
 
2
)
 
2
(Si
 
2
O
 
5
)
 
3
·4H
 
2
O
14.16.6Boltwoodite
(K,Na)(UO
 
2
)[HSiO
 
4
] · 0.5H
 
2
O
14.16.7Natroboltwoodite
(H
 
3
O)(Na,K)UO
 
2
SiO
 
4
·H
 
2
O
14.16.8Cuprosklodowskite
Cu(UO
 
2
)
 
2
[HSiO
 
4
]
 
2
 · 6H
 
2
O
14.16.9Sklodowskite
Mg(UO
 
2
)
 
2
[HSiO
 
4
]
 
2
 · 5H
 
2
O
14.16.10Uranophane
Ca(UO
 
2
)
 
2
[HSiO
 
4
]
 
2
 · 5H
 
2
O
14.16.11β-Uranophane
Ca(UO
 
2
)
 
2
[HSiO
 
4
]
 
2
 · 5H
 
2
O
14.16.12Haiweeite
Ca(UO
 
2
)
 
2
[Si
 
5
O
 
12
(OH)
 
2
]·4.5H
 
2
O
14.16.13Metahaiweeite
Ca(UO
 
2
)
 
2
Si
 
6
O
 
15
·nH
 
2
O
14.16.14Thorogummite
(Th,U)[(OH)
 
4x
|(SiO
 
4
)
 
1-x
]
14.16.16Ekanite
(Ca,Fe
2+
 
,Pb)
 
2
(Th,U)[Si
 
8
O
 
20
]
14.16.17Kasolite
Pb(UO
 
2
)[SiO
 
4
] · H
 
2
O
14.16.18 Orlite
Pb
 
3
(UO
 
2
)
 
3
(Si
 
2
O
 
7
)
 
2
·6H
 
2
O
14.16.19Oursinite
(Co,Mg)(UO
 
2
)
 
2
[HSiO
 
4
]
 
2
 · 6H
 
2
O

Other Names for Steacyite

Synonyms:
IMA1981-EUnnamed (MSH UK-4)
Other Languages:
German:Steacyit
Spanish:Steacyita

Other Information

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

References for Steacyite

Reference List:Canadian Mineralogist (1982): 20: 59-63.

American Mineralogist (1983): 68: 472.

Acta Crystallographica: B28: 1994-1999.

European Journal of Mineralogy (1993): 5: 971.

Internet Links for Steacyite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Steacyite in the Natural History Museum (London) online catalogue
  • Steacyite details from Handbook of Mineralogy (PDF)
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    Localities for Steacyite

    Hide Locality List
    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Canada
     
    • Québec
      • Montérégie
        • Rouville RCM
          • Mont Saint-Hilaire
    		Can.Min.(1982) 20, 59-63; Horváth, L and Gault, R.A. (1990), The mineralogy of Mont Saint-Hilaire Quebec. Mineralogical Record: 21: 284-359.
    Germany
     
    • Rhineland-Palatinate
      • Eifel Mts
        • Laach lake volcanic complex
          • Kruft
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (IX), Mineralien-Welt 5/1,18, 1994
          • Mendig
            • Niedermendig
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (IX), Mineralien-Welt 5/1,18, 1994
    Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (IX), Mineralien-Welt 5/1,18, 1994
              • Wingertsberg Mt.
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (IX), Mineralien-Welt 5/1,18, 1994
    Greenland
     
    • Kitaa (West Greenland) Province
      • Narsaq
        • Igaliku (Igaliko)
          • Narssârssuk (Narsarsuk)
    		Knut Eldjarn ( XRD Geological museum, Oslo)+ chemical (ICP)
    Guinea
     
    Parodi, G. C., & Della Ventura, G. (1987). Steacyite from the Rouma Isle (Los Islands, Republic of Guinea). Neues Jarbuch fur Mineralogie, Mh., Jg. 1987, H. 5, 233-239
    Parodi, G. C., & Della Ventura, G. (1987). Steacyite from the Rouma Isle (Los Islands, Republic of Guinea). Neues Jarbuch fur Mineralogie, Mh., Jg. 1987, H. 5, 233-239.
    Russia
     
    • Eastern-Siberian Region
      • Saha Republic (Sakha Republic; Yakutia)
        • Aldan Shield
          • Chara and Tokko Rivers Confluence
    		Konev, A.A., Vorob\'yev, E.I., and Lazebnik, K.A. (1996) The Mineralogy of the Murun Massif. Russian Academy of Science Press, Siberian Branch, Novosbirsk, Russia (in Rus.)
    Pavel M. Kartashov data
    • Northern Region
      • Murmanskaja Oblast'
        • Kola Peninsula
          • Khibiny Massif
    		Pekov, I.V. & Podlesnyi, A.S. (2004): Kukisvumchorr Deposit: Mineralogy of Alkaline Pegmatites and Hydrotermalites. Mineralogical Almanac, vol. 7, 140 pages + xxiv photo's pages
    Tajikistan
     
    • Region of Republican Subordination
      • Tien Shan Mts
        • Alai (Alayskiy) Range
    		[Lapis 1991:12 p.42-48]
    USA
     
    Leonard S.Wiener and Sigrid Ballew,1995, Updated by Kenny Gay,2006, A Listing Of North Carolina Minerals,Geologic Note No.4
    Minerological Record 18: 361n
    Mineral and/or Locality
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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 9th Oct 2009 18:58:01