Discovered in Greenland in the late 1890's, hackmanite is named for Finnish geologist Victor Hackman. It is a rare occurrence to find gem-grade hackmanite; at best, most crystals are translucent. Hackmanite is the light pink to pale violet variety of sodalite. It is a particularly unusual gem because it exhibits a special optical property known as "tenebrescence," a type of reversible photochromism.
Hackmanite is very reactive under UV light.