Steacyite
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Steacyite is a mineral, a complex silicate containing thorium and uranium; formula Kvariable(Ca,Na)2ThUSi8O20. 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 mineralogist.[1]