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 long wave 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 current group comprises oval, circular and cushion-shaped hackmanite cabochons with various hues of lavender to pastel violet. When seen under the UV light, one can see bright orange hue as the hackmanite is a tenebrescent mineral. Total weighing approximately 47.66 carats (15)