Chemical Formula: SiO2 nH2O
Status: IMA-GP
Crystal System: Amorphous
Mineral for Display: Yes
Associated names (luminescent varieties, discredited names, synonymes etc.): cacholong, hyalite, hydrophane, quincite (quincyite), geyserite, lussatite,UV Type | Main color | Intensity | Observation Frequency |
---|---|---|---|
Long Waves (365nm): | Yellowish Green | Short Waves (254 nm): | Yellowish Green |
Other colors LW: | Yellowish White , Greenish Yellow , Yellowish Green , Green , Bluish Green , Greenish white , Yellowish , | ||
Other colors MW: | Greenish Yellow , Yellowish Green , Green , Bluish Green , | ||
Other colors SW: | Yellowish White , Pale Yellow , Yellow , Orangy yellow , Greenish Yellow , Yellowish Green , Green , Bluish Green , Greenish white , Yellowish , |
Daylight Picture
OPALE, Nevada, USA;
Col. G. Barmarin; Photo: G. Barmarin
Long Waves Picture (365nm)
OPALE, Nevada, USA; LW (365 nm).
Col. G. Barmarin; Photo: G. Barmarin
Short Waves Pictures (254nm)
OPALE, Nevada, USA; SW (255 nm).
Col. G. Barmarin; Photo: G. Barmarin
Galerie de photos:
...To the gallery (13 images in the gallery)
UV Type | Color | Intensity | Observation Frequency |
---|---|---|---|
Short Waves (254 nm): | Greenish Yellow | Strong | Rarely |
Most Common Activator: (UO2)2+ (Uranyl ion) as impurities
Peaks in the spectrum (nm):
UO22+ : 504nm, 524nm, 547nm, 569nm, 601nm (opale Nevada, USA)
Col. G. Barmarin; Spectre: G. Barmarin
To the spectrum gallery (2 spectra in the gallery)
Green luminescence related to uranium impurities.
Georges O. Wild from Idar Oberstein in Germany found as early as 1947 that the greenish yellow fluorescence of opal from Virgin Valley, Nevada was due to uranium traces and being identical of the fluorescence of the synthetic gemstone Emerada (synthetic spinel).
Wild cites a weak band at 600 to 605nm, strong band at 570 to 578nm, strong band at 545 to 550nm, medium band at 522 to 527nm and weak band at 500 to 503nm.
Before Wild, DeMent has already studied the spectrum of opal s luminescence before Wild but not as precisely.
(*)Data are not exhaustive and are limited to the most important localities for fluorescence
Images:
Videos:
http://www.mindat.org/show.php?name=Opale
http://webmineral.com/data/Opale.shtml
Search for images on 'Google Image'
Search for documents in English on Google
Search for documents in any languages on Google