Steacyite

Steacyite
General
Category	Cyclosilicate
Formula (repeating unit)	Kvariable(Ca,Na)2(Th,U)Si8O20
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	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.

References

Notes

Sources

• Handbook of Mineralogy
• mindat page for steacyite

See also

• List of minerals
• List of minerals named after people