Chemistry:Steacyite

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Steacyite
Steacyite.jpg
Steacyite crystals from the type locality of Mont-Saint-Hilaire, Quebec
General
CategoryCyclosilicate
Formula
(repeating unit)
K
variable
(Ca,Na)
2
(Th,U)Si
8
O
20
Strunz classification9.CH.10
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space groupP4/mcc
Identification
ColorGray, dark brown, green, beige
Mohs scale hardness5
|re|er}}Vitreous, greasy, dull
DiaphaneityTranslucent, opaque
Other characteristicsRadioactive.svg Radioactive

Steacyite is a complex silicate mineral containing thorium and uranium; formula K
variable
(Ca,Na)
2
(Th,U)Si
8
O
20
. 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.[1]

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See also