Chemical Formula:See CHRYSOBERYL
Familly: Oxides and hydroxides
Status: NON APPR
Crystal System: Orthorhombic
Mineral for Display: No
UV Type | Main color | Intensity | Observation Frequency |
---|---|---|---|
Long Waves (365nm): | Red | Weak | Mid waves (320 nm): | Red | Short Waves (254 nm): | Red | Weak |
Other colors LW: | Greenish white , |
CHRYSOBERYL var. alexandrite
Most Common Activator: Cr3+
Other activators: Mn4+ , V2+ ,
Peaks in the spectrum (nm):
663, 664, Cr3+ II : 679, 680nm Cr3+ I : 689, 690, 693, 694nm Cr3+ : 701, 707, 720, 721nm Broad band peaking at +/- 600 V2+ (?) : broad band peaking at +/- 717nm Mn4+ : broad bands around 650 - 670nm
Spectrum: Michael Gaft, Petah Tikva, Israel. Plot: Institute of Mineralogy, University of Vienna, Austria, with permission of the authors.
To the spectrum gallery (5 spectra in the gallery)
Two types of Cr3+ luminescence centers have been found in natural alexandrite, characterized at 300 K by R-lines at approximately 679.0 with 677.3 nm and 694.4 with 691.7 nm, accompanied by very many N-lines of Cr-Cr pairs. Those centers have been identified as connected with substitutions of Al3+ in different structural sites (Tarashchan 1978). (Scalvi et al. 2003; Trindade et al. 2011)
(*)Data are not exhaustive and are limited to the most important localities for fluorescence
http://www.mindat.org/show.php?name=Alexandrite
http://webmineral.com/data/Alexandrite.shtml
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