Chemical Formula:See ELBAITE
Familly: Silicates
Status: NR
Crystal System: Rhomboedric
Mineral for Display: No
UV Type | Main color | Intensity | Observation Frequency |
---|---|---|---|
Long Waves (365nm): | Blue | Mid waves (320 nm): | Yellow |
Some very small crystals (a few mm) of achroïte from Elba Island are fluorescing the normal blue color under UV at 380nm and an unusual bright yellow fluorescence under UV at 306nm.
Activator is unknown, but the achroïte contain Mn and a very high amount of Mg (15-20%) but many non fluorescent tourmaline contain as much Mg.
Some very small crystals of achroïte included in quartz are practically only detectable by their strong yellow fluorescence.
Other colored tourmaline (pink, yellow and green) from Elba show sometimes a very weak yellow fluorescence.
Most Common Activator:
Peaks in the spectrum (nm):
Excitation 380nm: 439nm; Excitation 306nm: 350nm and 568nm;
(*)Data are not exhaustive and are limited to the most important localities for fluorescence
http://www.mindat.org/show.php?name=Achroite
http://webmineral.com/data/Achroite.shtml
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