Zektzerite and Albite from Washington Pass, Washington
Contributed by: Michael Crawford
Date: Sep 1st, 2025
Locality: Washington Pass, Golden Horn Batholith, Okanogan County, Washington, USA (See on Mindat)
Size: 20 x 25 mm
Description:
A thumbnail specimen of pinkish zektzerite (LiNaZrSi6O15) and white albite (Na(AlSi3O8)) from Washington Pass, Okanogan County, Washington. The zektzerite fluoresces bluish white and the albite fluoresces red under shortwave UV light. There is no fluorescence under longwave and midwave UV light. The specimen also contains non-fluorescent black arfvedsonite and golden blades of astrophyllite within the zektzerite crystals.
The shortwave emission spectrum of zektzerite is a broad peak with a maximum at 460 nm. The zektzerite fluorescence is activated by titanium-oxygen (Ti-O) substituting for zirconium-oxygen (Zr-O). The red fluorescence of albite is activated by ferric iron (Fe3+) replacing aluminum (Al3+). The emission spectrum peaks in the near infrared with a maximum at 713 nm.
The monochrome image of the near infrared fluorescence clearly shows the areas of albite fluorescence as bright white. In the color infrared image, the albite is orange and the zektzerite is blue. Within the blue areas of zektzerite are red patches that appear non-fluorescent in the shortwave image, but the mineral has near infrared fluorescence. The areas are too small to measure a spectrum. The red patches are likely feldspar, possibly microcline or albite with a different concentration of the iron activator.
Summary of luminescence responses:
Zektzerite (Mindat) (RRUFF)
- Fluorescence under Shortwave (255nm LED) UV light: White
- Fluorescence under Shortwave (255nm LED) UV light: Red