Steacyite

Steacyite
Steacyite crystals from the type locality of Mont-Saint-Hilaire, Quebec
General
CategoryCyclosilicate
Formula
(repeating unit)
Kvariable(Ca,Na)2(Th,U)Si8O20
IMA symbolScy[1]
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
LusterVitreous, greasy, dull
DiaphaneityTranslucent, opaque
Other characteristics Radioactive

Steacyite is a complex silicate mineral containing thorium and uranium; formula Kvariable(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]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Dunn, P.J.; Fleischer, M.; Burns, R.G.; Pabst, A. (1983). "New mineral names" (PDF). American Mineralogist. 68: 471–000. Retrieved 14 March 2022.