Hackmanite is a very rare species in crystalline form, and seldom do you find rich specimens such as this piece, which is also a well known cover specimen from a 2021 Gems & Gemology issue (the journal of the GIA, Gem Institute of America). This specimen features a rich cluster of sharp defined crystals to 1 cm, perched on matrix. It glows like a banshee at the first hint of UV light from a lamp, but also from just sunlight. It is not only fluorescent, but also tenebrescent, in that the color stays strong after the UV is removed. This is because the excited state of the electrons from UV light persists for some time after "charging" so that it literally keeps glowing with hot neon color, even after the UV source is removed. We have tried to capture the vivid tenebrescence in the video of this specimen but it is hard to convey in video or photo how strong this effect is in person. It is actually shocking. They go from lavender purple to hot orange, and then a hot neon purple after the UV is removed. This color persists for some time, minutes to hours, depending on the strength of the light source. Hackmanite is one of the most visible instances of this effect in gems. This particular specimen came out long ago, and was in the collection of notable collector and gem expert, Bill Larson.