Tenebrescence
Tenebrescence, also known as reversible photochromism, is the ability of minerals to change colour when exposed to light. The effect can be repeated indefinitely, but is destroyed by heating.[1]
Tenebrescent minerals include hackmanite, spodumene and tugtupite.
Tenebrescent behavior is exploited in synthetic materials for the manufacture of self-adjusting sunglasses, which darken on exposure to sunlight.
References
- ^ Kondo, D.; Beaton, D. (2009). "Hackmanite/Sodalite from Myanmar and Afghanistan" (PDF). Gems and Gemology. 45 (1): 38–43. doi:10.5741/GEMS.45.1.38.
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