Chrysoberyl from New Hampshire
Contributed by: Michael Crawford
Date: Jul 25th, 2025
Locality: Globe Mine, Springfield, Sullivan County, New Hampshire, USA (See on Mindat)
Size: 2.5 x 5 cm
Description:
A specimen of chrysoberyl (BeAl2O4) from the Globe Mine, New Hampshire. The chrysoberyl fluoresces red under longwave UV light. The fluorescence is yellow under midwave and shortwave UV light.
The longwave emission spectrum has a sharp peak at 679 nm that is activated chromium (Cr3+) that replaces aluminum is the chrysoberyl structure. According to fluomin.org, Al3+ ions are octahedrally coordinated with oxygen ions and the Al3+ ions occur in two non-equivalent crystal field sites in the chrysoberyl lattice. 78% of the Cr3+ ions replace Al3+ ions in one site and the rest go into the second AL3+ site (https://fluomin.org/uk/fiche.php?id=291). The yellow midwave and shortwave may be activated by TiO6
Summary of luminescence responses:
Chrysoberyl (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Red
- Fluorescence under Midwave (305nm LED) UV light: Yellow
- Fluorescence under Shortwave (255nm LED) UV light: Yellow