From the desert of southern Arizona, this is a very ordinary and nondescript looking rock in daylight, as is the case with many fluorescent mineral specimens. It contains wickenburgite, willemite and fluorite, and was collected from the Potter-Cramer Mine, near Wickenburg. Under the light of the UV lamp however, this rock comes to life, showing a beautiful multi-colored fluorescent response. Under short wave the wickenburgite glows magenta/red, the willemite pale green/blue, and the fluorite deep blue. The Willemite is also brightly phosphorescent for an extended period of time. Under long wave UV, the fluorite shows a classic deep blue/purple response. The size of this specimen is 51 x 47 x 37 mm, and it weighs 70 grams.
The Potter-Cramer Mine is located in the Vulture Mountains, south of Wickenburg, Arizona. It is also the type location for the mineral wickenburgite, meaning that the mineral was first discovered there. The mine has been a producer of zinc, lead, copper, gold, vanadium, and wickenburgite specimens.