Opal CL/PL measurement, 77K, Gorobets and Rogojine 2002; Gotze 2000

Reference	Gorobets B.S., Rogojine A.A. (2002). Luminescent Spectra of Minerals: Reference Book. All-Russia Institute of Mineral Resources. Moscow. - P. 208. - Fig. 13.3. - P. 264. - Fig. 23.2.
Material	Opal [ SiO₂·nH₂O ] Dark Jubilee Opal specimen (318.44ct) from Coober Pedy, South Australia, Australia © Photo by Chip Clark, via Smithsonian National Museum of Natural History
Specimen temperature	77K
Technique	CL/PL
Lines	Singlet-triplet 500 nm, Unspecified 490 nm

Nominal composition of Opal [ SiO₂·nH₂O ].
Element	Atoms	At%	Wt%
H	3.47	3.47	0.181
Si	32.24	32.24	46.73
O	64.29	64.29	53.09