Multi-wavelength Tenebrescent Hackmanite - Sudbury District, Ontario, Canada
Contributed by: FMS Admin
minID: 893-Q12
Date: May 17th, 2026
Locality: Sudbury District, Ontario, Canada (See on Mindat)
Size: 7.1 x 3.1 x 10.3 cm
Description:
Shown here is a nice cabinet-sized specimen of sodalite var. hackmanite, from a recent find in the District of Sudbury, in Ontario, Canada. It is associated with feldspar, which fluoresces dull red under SW (stronger in person than in the SW picture shown in the slideshow below); and the face of the specimen, which was split along a crack in the rock, is partially covered with greenish fluorescing calcite that once filled the crack. This calcite coating is phosphorescent upon exposure to all UV wavelengths (LW shown); the hackmanite is nicely tenebrescent upon exposure to both SW and MW (only SW is shown here), and mildly tenebrescent upon LW exposure.
Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2021.
Summary of luminescence responses:
Hackmanite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Yellow
- Fluorescence under Midwave (305nm LED) UV light: Orange
- Fluorescence under Shortwave (255nm LED) UV light: Red
- Tenebrescence after exposure to Longwave (365nm LED) UV light: Purple
- Tenebrescence after exposure to Shortwave (255nm LED) UV light: Purple