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Steacyite

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

Show Steacyite Photos (20)
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 Co., 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

Related to:
  • 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)
    German names:
    Steacyit
    Spanish names:
    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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  • Look for Steacyite on Wikipedia
  • Look for Steacyite on Mineralien Atlas
  • 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.
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    (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
      • Rouville Co.
        • 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)
    		[World of Stones 12:49]
    • 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
        • Alayskiy (Alai) 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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