Steacyite
A valid IMA mineral species
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About Steacyite
Formula:
K0.3(Na,Ca)2ThSi8O20
Colour:
Gray, dark brown, green, beige
Lustre:
Vitreous, Greasy, Dull
Hardness:
5
Specific Gravity:
2.95
Crystal System:
Tetragonal
Member of:
Name:
Named in 1982 by Guy Perrault and Jan T. SzymaĆski in honor of Harold Robert Steacy [June 7, 1923 Ottawa, Ontario, Canada - April 7, 2012 Ottawa, Ontario, Canada], mineralogist, former Curator of the National Mineral Collection, Geological Survey of Canada, for his contributions to Canadian mineralogy.
This page provides mineralogical data about Steacyite.
Unique Identifiers
Mindat ID:
3754
Long-form identifier:
mindat:1:1:3754:5
GUID
(UUID V4):
(UUID V4):
e30a4d1b-af89-47ed-be55-4dc4d1a94991
IMA Classification of Steacyite
Classification of Steacyite
9.CH.10
9 : SILICATES (Germanates)
C : Cyclosilicates
H : [Si4O12]8- 4-membered double rings
9 : SILICATES (Germanates)
C : Cyclosilicates
H : [Si4O12]8- 4-membered double rings
63.1.1.1
63 : CYCLOSILICATES Condensed Rings
1 : Condensed Rings (Steacyite group)
63 : CYCLOSILICATES Condensed Rings
1 : Condensed Rings (Steacyite group)
14.16.15
14 : Silicates not Containing Aluminum
16 : Silicates of U
14 : Silicates not Containing Aluminum
16 : Silicates of U
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Symbol | Source | Reference |
---|---|---|
Scy | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Stc | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Steacyite
Vitreous, Greasy, Dull
Transparency:
Translucent, Opaque
Colour:
Gray, dark brown, green, beige
Hardness:
5 on Mohs scale
Cleavage:
None Observed
Density:
2.95 g/cm3 (Measured) 3.32 g/cm3 (Calculated)
Comment:
Measured on porous material.
Optical Data of Steacyite
Type:
Uniaxial (-)
RI values:
nω = 1.573 nε = 1.572
Max Birefringence:
δ = 0.001
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Chemistry of Steacyite
Mindat Formula:
K0.3(Na,Ca)2ThSi8O20
Common Impurities:
As,Mn,Pb,F,P
Crystallography of Steacyite
Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
P4/mcc
Setting:
P4/mcc
Cell Parameters:
a = 7.58 Å, c = 14.76 Å
Ratio:
a:c = 1 : 1.947
Unit Cell V:
848.06 Ă
Âł (Calculated from Unit Cell)
Morphology:
Elongated along [001] and showing only the forms {100} and {001}.
Twinning:
Cruciform, by 90° rotation about [010].
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
---|---|---|---|---|---|---|---|
0018511 | Steacyite | Prichard P, Perrault G (1972) Structure cristalline de l'ekanite de St-Hilaire, P.Q. Acta Crystallographica B28 1994-1999 | 1972 | Mont St-Hilaire, Quebec, Canada | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
3.38 Ă | (100) |
3.32 Ă | (55) |
5.30 Ă | (45) |
2.64 Ă | (41) |
2.00 Ă | (26) |
1.82 Ă | (20) |
2.16 Ă | (19) |
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 4b: Highly evolved igneous rocks | >3.0 |
34 : Complex granite pegmatites | |
35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Steacyite
General Appearance of Type Material:
Elongated crystals to 2 mm.
Place of Conservation of Type Material:
Ecole Polytechnique, Montreal, Quebec, Canada, number 12480.
Canadian Geological Survey, Ottawa, Ontario, Canada, number 61529.
Canadian Museum of Nature, Ottawa, Canada.
National Museum of Natural History, Washington, D.C., USA, number 149820.
The Natural History Museum, London, England, number 1970,168.
Canadian Geological Survey, Ottawa, Ontario, Canada, number 61529.
Canadian Museum of Nature, Ottawa, Canada.
National Museum of Natural History, Washington, D.C., USA, number 149820.
The Natural History Museum, London, England, number 1970,168.
Geological Setting of Type Material:
In pegmatite veins in nepheline syenite.
Associated Minerals at Type Locality:
Synonyms of Steacyite
Other Language Names for Steacyite
German:Steacyit
Russian:ĐĄŃĐžŃООŃ
Simplified Chinese:æŻçĄ
éŸééçł
Spanish:Steacyita
Traditional Chinese:æŻçœéé·éŁçł
Relationship of Steacyite to other Species
Member of:
Other Members of this group:
Arapovite | (K1-xâ»x)(Ca,Na)2U4+Si8O20 (x ~ 0.5) | Tet. 4/mmm (4/m 2/m 2/m) : P4/mcc |
Iraqite-(La) | KCa2(La,Ce,Th)Si8O20 | Tet. 4/mmm (4/m 2/m 2/m) : P4/mcc |
Turkestanite | (K,â»)(Ca,Na)2ThSi8O20 · nH2O | Tet. 4/mmm (4/m 2/m 2/m) : P4/mcc |
Common Associates
Associated Minerals Based on Photo Data:
48 photos of Steacyite associated with Charoite | (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 · ~3H2O |
47 photos of Steacyite associated with Aegirine | NaFe3+Si2O6 |
14 photos of Steacyite associated with Quartz | SiO2 |
12 photos of Steacyite associated with Pectolite | NaCa2Si3O8(OH) |
11 photos of Steacyite associated with Galena | PbS |
4 photos of Steacyite associated with Microcline | K(AlSi3O8) |
4 photos of Steacyite associated with Frankamenite | K3Na3Ca5(Si12O30)(F,OH)4 · H2O |
3 photos of Steacyite associated with Gjerdingenite-Na | K2Na(Nb,Ti)4(Si4O12)2(OH,O)4 · 5H2O |
3 photos of Steacyite associated with Tinaksite | K2Na(Ca,Mn2+)2TiO[Si7O18(OH)] |
2 photos of Steacyite associated with Sazhinite |
Related Minerals - Strunz-mindat Grouping
9.CH.05 | Hyalotekite | (Ba,Pb,K)4(Ca,Y)2(B,Be)2(Si,B)2Si8O28(F,Cl) |
9.CH.05 | Kapitsaite-(Y) | (Ba,K,Pb)4(Y,Ca)2Si8(B,Si)4O28F |
9.CH.05 | Itsiite | Ba4Ca2[Si8B4O28]â» |
9.CH.05 | Khvorovite | (Pb,Ba,K)4Ca2[Si8B2(Si,B)2O28]F |
9.CH.10 | Iraqite-(La) | KCa2(La,Ce,Th)Si8O20 |
9.CH.10 | Turkestanite | (K,â»)(Ca,Na)2ThSi8O20 · nH2O |
9.CH.10 | Arapovite | (K1-xâ»x)(Ca,Na)2U4+Si8O20 (x ~ 0.5) |
Other Information
Notes:
Radioactive. Emits α and ÎČ particles, but not Îł radiation.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Steacyite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Steacyite
mindat.org URL:
https://www.mindat.org/min-3754.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Steacyite
Reference List:
Perrault, G., SzymaĆski, J. T. (1982) Steacyite, a new name and a re-evaluation of the nomenclature of "ekanite"-group minerals. The Canadian Mineralogist, 20 (1) 59-63
Localities for Steacyite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
All localities listed without proper references should be considered as questionable.
Canada (TL) | |
| Perrault et al. (1982) +2 other references |
Germany | |
| Blass et al. (1994) |
Greenland | |
| Knut Eldjarn ( XRD Geological museum, Oslo) |
Guinea | |
| Parodi et al. (1987) |
a magmatic marker of the evolution of the Central and Equatorial Atlantic. The Canadian Mineralogist (2) +3 other references | |
Namibia | |
| Joachim Esche collection (SEM-EDS-analysed) +3 other references |
Portugal | |
| Chiappino et al. (2015) |
| Pedro Alves collection and analytical ... |
Russia | |
| Konev et al. (1996) |
Kaneva +3 other references | |
Pavel.M. Kartashov (n.d.) +1 other reference | |
Kaneva +3 other references | |
| Pekov et al. (2004) |
USA | |
Minerological Record 18: 361n |
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Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada