In the early 1800's geologists noted that some specimens of sodalite from Greenland exhibited a bright pink color on freshly broken surfaces. This color rapidly faded ("bleached") upon exposure to bright light, reverting back to its original (natural?) color. Exposure...
The following article is the summary of multiple conversations from the Fluorescent Minerals Facebook group, where people experimented with tenebrescent minerals and reported their observations. Tenebrescence is a reversible photochromic phenomenon in which a mineral...
This article was originally published on Nature’s Rainbow. Tenebrescence of Greenland sodalite is amazing. This is a piece of a deeply tenebrescent sodalite. Note how when the SW light is first turned on the sodalite fluoresces a bright orange but almost immediately...