Kyanite from Skardu, Pakistan
Contributed by: Michael Crawford
Date: Aug 23rd, 2025
Locality: Skardu Area, Gilgit-Baltistan, Pakistan (See on Mindat)
Size: 8 x 12 cm
Description:
Blue kyanite (Al2(SiO4)O) crystals in a quartz matrix from Skardu, Pakistan. The kyanite fluoresces bright red under longwave UV illumination. It is non-fluorescent under midwave and shortwave UV light.
The emission spectrum has two large very sharp peaks at 688 nm and 704 nm. There are two smaller peaks at 723 nm and 733 nm. These sharp peaks are superimposed on a broader peak. Most of this broader peak is in the near infrared with a maximum around 730 nm. The fluorescence is activated by chromium (Cr3+) replacing aluminum (Al3+). According to fluomin.org, there are three different aluminum sites in kyanite where chromium can substitute that are responsible for the sharp and broad peaks in the emission spectrum.
Summary of luminescence responses:
Kyanite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Red