Color Change Sodalite: Hackmanite Rough and Cut A Fluorescent and Tenebrescent Mineral
Named after the Finnish geologist, Victor Hackman, hackmanite is an important variety of sodalite which exhibits the phenomenon of tenebrescence. When freshly mined, it is generally white or green but develops a violet to pink-red color in sunlight. If left in a dark environment for some time, the violet will fade again. Tenebrescence is accelerated by the use of longwave or, particularly, shortwave ultraviolet light. Sodalite that shows this behavior is known as hackmanite. Very few minerals exhibit this phenomenon which is also known as reversible photochromism, a word that applies to sunglasses which change color density on exposure to sunlight.
The present rough is a brilliant fushcia pink the color of which will strengthen upon exposure to sunlight, measuring 1 ¼ x 1 x ½ in; together with an oval cabochon of lavender hue weighing approximately 19.09 carats and measuring 18.0 x 16.0 x 11.0. Capable of being mounted as jewelry, this hackmanite stone would surely create a lively topic of conversation. (2)