From its beginnings the Thomas S. Warren Museum of Fluorescence was designed as an educational resource for teachers in the earth sciences and related fields. The Warren Museum, as part of the Sterling Hill Mining Museum Foundation, is an accredited facility for providing continuing education for high-school teachers for maintenance of their teaching certifications. Workshops related to the nature of fluorescence and its uses in industry, technology, and commerce are part of the Foundation curriculum, as are other workshops on the geology and mining history of New Jersey, the role of mining in everyday life, etc. Most of these workshops are taught during the summer months when teachers are off. For information on workshops currently offered call Steve Misiur at 973-209-7212 after 5 p.m. and leave message, or send e-mail to shmm@sussexonline.com.

K-12 teachers who visit the museum with their classes will also find much information available to them. As befits its association with a mining museum, and in keeping with the lifelong interest of its namesake, the Warren Museum has on display numerous fluorescent minerals, rocks, and ores. Nearly every exhibit in the museum illustrates some central theme and contains explanatory material to facilitate student comprehension. Moreover, as the museum's name implies, the entire realm of fluorescence is within its purview, and our future exhibits and educational efforts will reflect that broader view.

A list of current exhibits in the Warren Museum follows.

Displays of Single Mineral Species

Calcite case: The specimens in this case are all the same mineral—calcite—but they show a wide range in color of fluorescence, including red, green, blue, orange, yellow, white, and more.

	Calcite from around the world. Click image for larger view. Photo by Tema Hecht.

That a single mineral species can fluoresce in so many different colors highlights both the beauty and complexity of fluorescence in minerals. In viewing this case visitors will realize immediately that fluorescence cannot have a single cause.

Fluorite case: Fluorite, like calcite, shows a wide range in color of fluorescence, again due to multiple causes. In this case are specimens fluorescing red, white to cream, and green, as well as those fluorescing the usual deep blue to blue-violet.

Willemite case: One of the principal ore minerals of the local zinc mines, willemite from Franklin and Sterling Hill is renowned for its bright yellowish-green fluorescence. Willemite from other localities, however, commonly fluoresces white or pale yellow. Specimens from worldwide localities illustrate the range in color of fluorescence in this important mineral species.

	Scheelite from around the world. Click image for larger view. Photo by Tema Hecht.

Scheelite case: As a counterpoint to the calcite, fluorite, and willemite cases, the scheelite specimens in this case are from worldwide localities but show little diversity in their color of fluorescence. Unlike those other minerals, scheelite is a "self-activated" mineral—that is, its fluorescence is due to the mineral itself rather than to some chance chemical impurity or other cause. The characteristic blue to bluish-white fluorescence of this species is a valuable property in prospecting for scheelite deposits at night.

Displays About Activators of Fluorescence

Activators case: A label accompanying each specimen in this case identifies the cause of its fluorescence. Viewers learn that fluorescence commonly is due to inorganic chemical impurities, generally of metallic elements such as manganese, titanium, and the rare-earth metals, but occasionally of nonmetallic elements as well. Other minerals fluoresce due to included organic matter (microscopic droplets of petroleum in fluorite) or to nearly invisible coatings of a second mineral or alteration product.

	Activators case (partial view). On left, zircon activated by trivalent dysprosium. On right, tugtupite activated by disulfide ion. Photo by Herb Yeates.

Manganese-activated minerals: The fluorescence of every specimen in this display is due to manganese. The colors of fluorescence span a broad range, from red through orange and yellow to green, showing that manganese causes different colors of fluorescence in different minerals. The colors are not accidental but depend on the atomic structure of the mineral in which the manganese is present.

	Uranyl-activated minerals (partial view). Photo by Tema Hecht.

Uranyl-activated minerals: The characteristic yellow-green fluorescence of uranyl-activated minerals is evident in all of the specimens in this case. Unlike manganese, the uranyl ion in minerals is insensitive to its atomic environment, and thus a similar color of fluorescence appears regardless of the mineral species.

Locality Displays

Northeastern U.S. case: Though mining has all but ceased in the northeastern United States, this region is still a prolific source of fine fluorescent mineral specimens. 

	Northeastern U.S. case (partial view). Click image for larger view. Photo by Maureen Verbeek.

Most of the specimens in this case were collected during the 1990s or later, showing that some important localities are still productive and that others have been discovered only recently. The millions of people who live in the northeastern part of the nation are ideally situated to pursue collecting fluorescent minerals as a hobby.

Fluorescent minerals of Arizona: Tens of thousands of abandoned mines in the deserts and mountains of Arizona provide fertile hunting grounds for collectors of fluorescent minerals, as the specimens in this case reveal. Recent advances in ultraviolet lamp technology have caused increasing numbers of collectors to take to the field in search of minerals for enjoyment and scientific research.

Miscellaneous Displays

Fossils: Fossils often fluoresce in various pastel colors due to remaining traces of organic material, or they fluoresce green due to local concentrations of uranium-bearing minerals. 

	Fluorescent fossils (partial view). Photo by Tema Hecht.

The specimens in this case illustrate both of these general types and include fossil shells, coral, fish, bone, teeth, amber, and petrified wood. The presence of organic material in fossils tens to hundreds of millions of years old opens up exciting possibilities for partial DNA-typing of organisms long extinct.

Lapidary items: More than fifty fluorescent spheres, eggs, carvings, cabochons, and obelisks are presented in this case, devoted to the lapidary side of the fluorescent-mineral hobby. Visitors wearing gemstones, such as diamond rings or school rings, are invited to test them for fluorescence under the longwave ultraviolet lamps nearby.

	Lapidary items (partial view). Photo by Tema Hecht.

Nonmineral items: Fluorescence is exhibited by a broad range of materials in addition to minerals. The items in this case include such materials as glass, ceramics, wood, paper, fabric, plastic, and paint. Common household objects remind the visitor that one need not be interested in minerals to participate in the hobby of fluorescence.

Terlingua-type calcites: The calcite specimens in this case are from widely separate localities on two continents, but they all share several properties: under shortwave ultraviolet light they fluoresce bright blue, followed by an enduring phosphorescence of the same color, but under longwave ultraviolet light they fluoresce pink to apricot, and the phosphorescence is weak or absent. The cause of neither fluorescent response is known but is under investigation.

Terlingua-type calcite case. At left, lit by shortwave UV; at right longwave UV. Click image for larger view. Photos by Tema Hecht.

Ultraviolet lamps: Historic and modern ultraviolet lamps are displayed in two cases in a separate room in the museum. Visitors can follow the technological development of ultraviolet light sources from the iron spark generators used in the early 1900s through the efficient low-pressure mercury vapor lamps used today.

	Ultraviolet lamps. Click image for larger view. Photo by Tema Hecht.

Additional museum displays include a large fluorescent geode, a miniature mining scene, a large case of exceptionally aesthetic mineral specimens, and an antique fluorescent water cooler.