Hackmanite from Ladjuar Medam Richterite occurrence, Afghanistan

Hackmanite from Ladjuar Medam Richterite occurrence, Ladjuar Medam, Sar-e-Sang, Kuran wa Munjan District, Badakhshan, Afghanistan

Nice specimens of Hackmanite from the Ladjuar Medam Richterite occurrence, Sar-e-Sang, Afghanistan.

Hackmanite is an unusual mineral which demonstrates tenebrescence; the changing of colour when exposed to sunlight.

When exposed to a bright UV light, the mineral will fluoresce, and then when the UV light is turned off, the colour will be a slightly darker purple. However, this is not that pronounced in these specimens - the darker colour is normally much more pronounced - so best to just consider these specimens UV reactive, rather than demonstrably tenebrescent.