Steacyite

Steacyite
Steacyite
	File:Steacyite.jpg Steacyite crystals from the type locality of Mont-Saint-Hilaire, Quebec
General
Category	Cyclosilicate
Formula	Kvariable(Ca,Na)2(Th,U)Si8O20
IMA symbol	Scy
Strunz classification	9.CH.10
Crystal system	Tetragonal
Crystal class	Ditetragonal dipyramidal (4/mmm) ; H-M symbol: (4/m 2/m 2/m)
Space group	P4/mcc
Identification
Color	Gray, dark brown, green, beige
Mohs scale hardness	5
Luster	Vitreous, greasy, dull
Diaphaneity	Translucent, opaque
Other characteristics	File:Radioactive.svg Radioactive

Steacyite is a complex silicate mineral containing thorium and uranium; formula K_variable(Ca,Na)₂(Th,U)Si₈O₂₀. It forms small brown or yellow green crystals, often cruciform twinned crystals. It is radioactive. It was discovered at Mont-Saint-Hilaire, Quebec in 1982 and is named after Harold Robert Steacy (1923–2012), mineralogist.^[2]

References

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Steacyite
File:Steacyite.jpg Steacyite crystals from the type locality of Mont-Saint-Hilaire, Quebec
General
Category	Cyclosilicate
Formula	K_variable(Ca,Na)₂(Th,U)Si₈O₂₀
IMA symbol	Scy^[1]
Strunz classification	9.CH.10
Crystal system	Tetragonal
Crystal class	Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m)
Space group	P4/mcc
Identification
Color	Gray, dark brown, green, beige
Mohs scale hardness	5
Luster	Vitreous, greasy, dull
Diaphaneity	Translucent, opaque
Other characteristics	File:Radioactive.svg Radioactive