Steacyite

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Steacyite
Steacyite.jpg
Steacyite crystals from the type locality of Mont-Saint-Hilaire, Quebec
General
CategoryCyclosilicate
Formula
(repeating unit)
Kvariable(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
ColorGray, dark brown, green, beige
Mohs scale hardness5
Luster Vitreous, greasy, dull
Diaphaneity Translucent, opaque
Other characteristics Radioactive.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. [2]

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Ekanite is an uncommon silicate mineral with chemical formula Ca
2
ThSi
8
O
20
or (Ca,Fe,Pb)
2
(Th,U)Si
8
O
20
. It is a member of the steacyite group. It is among the few gemstones that are naturally radioactive. Most ekanite is mined in Sri Lanka, although deposits also occur in Russia and North America. Clear and well-colored stones are rare as the radioactivity tends to degrade the crystal matrix over time in a process known as metamictization.

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<span class="mw-page-title-main">Sturmanite</span>

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References

Notes

  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.

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See also