Emerald from the Khaltaro Valley, Pakistan
Contributed by: Michael Crawford
Date: Aug 29th, 2025
Locality: Khaltaro, Gilgit District, Gilgit-Baltistan, Pakistan (See on Mindat)
Size: 5 x 6 cm
Description:
Green crystals of emerald from the Khaltaro Valley, Haramosh Mountains, Gilgit District, Gilgit-Baltistan, Pakistan. Emerald is a variety of beryl (Be3Al2(Si6O18)). Trace amounts of chromium, vanadium, and iron are responsible for the green color in daylight. Chromium (Cr3+) and ferric iron (Fe3+) can also cause it to fluoresce under longwave UV light. The emerald is non-fluorescence under midwave and shortwave light. Many emeralds do not fluoresce. This emerald is unusual in that it fluoresces blue-green instead of the more typical red. The specimen also contains calcite that fluoresces white under longwave UV light.
The longwave emission spectrum of this emerald has a sharp peak at 684 nm caused by chromium. The sharp peak occurs on the shoulder of a much broader peak with a maximum in the near infrared at 715 nm. These two features of the spectrum are like the red fluorescent emerald spectrum. The difference between red and green fluorescent emerald is the broad peak at 492 nm. This is the green fluorescence emitted by the emerald. This green fluorescence may be activated by manganese or rare earths. More study is needed to understand this green fluorescence.
The last two images show the infrared fluorescence of the emerald.
Summary of luminescence responses:
Beryl var. Emerald (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Green