Scheikundige formule: ZrSiO4
Familie: Silicaten
Status: IMA-GP
Kristal Systeem: Tetragonaal
Mineraal om tentoon te stellen: Ja
Fluorescerende variëteiten: alvite, cyrtolite, malacon,UV Type | Kleur | Intensiteit | Frequentie van de observatie |
---|---|---|---|
Lange Golven (365nm): | Bleek geel | Zwak | Midden Golven (320 nm): | Oranje geel | Middelmatig | Korte Golven(254 nm): | Oranje geel | Sterk | Soms |
Andere kleuren lange golven: | Bruin , Geelachtig , | ||
Andere kleuren korte golven: | Gelig wit , Bleek geel , Geel , Bruin oranje , Bruin , Groenachtig , Geelachtig , |
Daglicht foto
Zircon, Rift Mineral Province, Malawi;
Col. G. Barmarin
Photo: Courtesy MinerShop.com
Korte golf foto (254nm)
Zircon, Rift Mineral Province, Malawi;
UVSW, Col. G. Barmarin
Photo: Courtesy MinerShop.com
Tenebrescencie: Ja
Thermoluminescencie: Ja
Variété alvite (contenant du Hf, Th et des terres rares: OC et LW: vert; SW: Rouge-orangé;
Variété cyrtolite (zircon partiellement métamicte contenant U et souvent Th et des terres rares: OC: jaune;
variété malacon (zircon très métamicte, souvent brun: OL: orange;
Zircon is ometimes thermoluminescent
Voornaamste Activator: Centra als gevolg van de effecten van straling
Andere activatoren: (UO2)2+ (Uranyl ion) (onzuiverheden) , Cr3+ , Fe3+ , Sm3+ , Eu3+ , Dy3+ , Ho3+ , Er3+ , Tb3+ , Nd3+ , Yb3+ , Tm3+ ,
Pieks in het spectrum (nm):
Dy3+ : 472, 481, 486nm (UO2)2+ : 506, 523, 550nm Fe3+ : 750 nm, Δ = 110–120 nm and τ = 3–5 ms Neutron and alpha irradiation : 575 nm, peak half-width (Δ) = 120–130 nm, and decay time (τ) = 30–35 µs
Spectrum: Michael Gaft, Petah Tikva, Israel. Plot: Institute of Mineralogy, University of Vienna, Austria, with permission of the authors.
Vers la galerie de spectres (12 spectres au total)
The crystal chemistry of zircon strongly favors the incorporation of REE in Zr4+ site. The REE impurities become luminescent in this crystallographic environment. The steady-state luminescence in natural zircons is dominated by broad emission arising from radiation induced centers and narrow emission lines of Dy3+ (Trofimov 1962; Tarashchan 1978). These emissions obscure the spectra of other REE. The thermal treatment enables to solve this problem in certain cases using the fact that the intensity of broad band luminescence quickly decreases after heating at 700 °C–800 °C, while the intensities of the REE lines remain nearly constant (Shinno 1986, 1987). Even after heating the samples not all the REE can be identified by steady-state spectroscopy since the weaker luminescence lines of certain REE are obscured by stronger luminescence of others. For example, the luminescence of Pr3+ is difficult to detect because the lines of Sm3+, Dy3+ and Nd3+ hide its radiative transitions. In turn, Tb3+ conceals luminescence of Tm3+ and so on. Different suppositions are made in previous studies and even the question about yellow luminescence connection with intrinsic or impurity defect remains open. The yellow band with peak wavelength (λmax) = 575 nm, peak half-width (Δ) = 120–130 nm, and decay time (τ) = 30–35 µs is connected with neutron and alpha irradiation. Activators: broadband emission from radiation induced centers and lines from Dy3+ (Trofimov in Gaft) masking other lines from REE in Zr4+ site.
The red band with λmax = 750 nm, Δ = 110–120 nm and τ = 3–5 ms is connected with Fe3+. (M. Gaft, I. Shinno, G. Panczer and R. Reisfeld, Laser-induced time-resolved spectroscopy of visible broad luminescence bands in zircon, Mineralogy and Petrology, vol76, 2002)
The intensity of the broadband luminescence quickly decrease after heating at 700-800° while the lines from REE stay constant (Shinno in Gaft).
(*)Gegevens zijn niet exhaustieve, ze zijn beperkt tot de meest belangrijke plaatsen voor fluorescentie
Images:
http://www.mindat.org/show.php?name=Zircon
http://webmineral.com/data/Zircon.shtml
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