Hauyne and Hackmanite from Afghanistan
Contributed by: Michael Crawford
Date: Jun 10th, 2025
Locality: Sar-e-Sang, Kuran wa Munjan District, Badakhshan, Afghanistan (See on Mindat)
Size: 10.5 x 19 cm
Description:
This specimen shows a cluster of dark green hauyne crystals with a purple hackmanite coating from Sar-e-Sang, Badakhshan Province, Afghanistan. The coating has chipped off in a couple of places revealing the dark green hauyne under the hackmanite.
The hackmanite is tenebrescent and phosphorescent. The phosphorescence is strongest after exposure to midwave light. The hauyne is neither tenebrescent or phosphorescent. Midwave fluorescence shows the greatest contrast between the hackmanite and hauyne.
This specimen was sold as a specimen of dark green sodalite and hackmanite. However, longwave emission spectra of the green mineral is a closer match to the emission spectrum of hauyne rather than sodalite. Hauyne is a member of the sodalite group. Hauyne has the same aluminosilicate cage network as sodalite but contains different anions and cations. Sodium and chlorine in sodalite (Na4(Si3Al3)O12Cl) are replaced by calcium and sulfate in hauyne (Na3Ca(Si3Al3)O12(SO4)). There may be some intermediate substitutions between sodalite-hauyne endmembers, but the size difference of the cations and anions limits continuous solid solution substitution like feldspar ground end members.
The longwave emission plots compare hauyne fluorescence in this specimen with hauyne fluorescence of specimens from Eifel, Germany and Ariccia, Rome, Italy. There is also a comparison with the fluorescence of a green sodalite specimen from Greenland. The vibronic peaks of the hauyne spectra have a much higher amplitude compared to the spectra of sodalite and hackmanite. These vibronic peaks are caused by a disulfide activator, and the higher amplitude may be caused by calcium creating a larger cage and more room for the disulfide to vibrate. The maximum brightness of hauyne is at a longer wavelength (around 620 nm) compared to sodalite (around 620 nm).
The midwave emission spectra show that the hauyne retains the vibronic peaks caused by the disulfide activator. The hackmanite spectrum has a broad peak with a maximum at 430 nm and the hauyne spectrum has a broad peak at 475 nm. Possible activators for these peaks in the blue region include dioxide, titanium, or REE’s.
Summary of luminescence responses:
Hauyne
- Fluorescence under Longwave (365nm LED) UV light: Orange
- Fluorescence under Midwave (305nm LED) UV light: Orange
- Fluorescence under Longwave (365nm LED) UV light: Orange
- Fluorescence under Midwave (305nm LED) UV light: White
- Fluorescence under Shortwave (255nm LED) UV light: White
- Afterglow after exposure to Midwave (305nm LED) UV light: White
- Afterglow after exposure to Shortwave (255nm LED) UV light: White
- Tenebrescence after exposure to Shortwave (255nm LED) UV light: Purple