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|System:||Tetragonal||Colour:||Gray, dark brown, green, ...|
|Name:||Named in 1982 by Guy Perrault and Jan T. Szymaňski 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.
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:||220.127.116.11|
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; Carrière Mont Saint-Hilaire), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada|
|Year of Discovery:||1981|
Physical Properties of Steacyite
|Lustre:||Vitreous, Greasy, Dull|
|Diaphaneity (Transparency):||Translucent, Opaque|
|Colour:||Gray, dark brown, green, beige|
Crystallography of Steacyite
|Cell Parameters:||a = 7.58Å, c = 14.76Å|
|Ratio:||a:c = 1 : 1.947|
|Unit Cell Volume:||V 848.06 Å³ (Calculated from Unit Cell)|
Optical Data of Steacyite
|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.
Chemical Properties of Steacyite
|Simplified for copy/paste:||(◻,K)(Na,Ca)2(Th,U)[Si8O20]|
|Essential elements:||Na, O, Si, Th|
|All elements listed in formula:||Ca, K, Na, O, Si, Th, U|
Relationship of Steacyite to other Species
|Member of:||Steacyite Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Steacyite
|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
PERRAULT, G., and SZYMAŃSKI, J.T. (1982) Steacyite, a new name and a re- evaluation of the nomenclature of "ekanite" group minerals. Canadian Mineralogist, 20, 59-63.
SZYMAŃSKY, J.T., OWENS, D.R., ROBERTS, A.C., ANSELL, H.G., and CHAO, G.Y. (1982) A mineralogical study and crystal structure determination of nonmetamict ekanite ThCa2Si8O20. Canadian Mineralogist, 20, 65-75.
Internet Links for Steacyite
|Specimens:||The following Steacyite specimens are currently listed for sale on minfind.com.|
Localities for Steacyite
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.
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