Hackmanite - Kola Peninsula, Russia
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Click to enlarge
Normal light
Longwave ultraviolet
This specimen has a unique characteristics of its own. Freshly exposed surface shows a bright raspberry red color which quickly fade in a few minutes when exposed to sunlight. The color can be restored by a few minutes of exposure to shortwave ultraviolet light. The longer the exposure time, the darker the color. When exposed to normal room light again, the red color will bleach out in a few minutes. The color also can be restored by storing it in a dark place for a few weeks to several months.

This phenomenon is called tenebrescence meaning photochromic.


Under longwave ultraviolet, it fluoresces brilliant peach to orange.
It's size is 2" long by 2" wide by 1" thick

Another mineral exhibits this behavior is Tugtupite.

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