Fluorescent minerals in UR museum light up the room

October 8, 2021

Photography

Whenever someone cuts the lights in the Lora Robins Gallery of Design from Nature’s Fluorescent Mineral Room, gasps and shrieks frequently ensue.

As the room darkens, the exhibition cases cycle through a series of ultraviolet lights, turning 300 ordinary-seeming rocks into a vivid array of neon colors. First, long-wave UV lights bring out ruby reds. Short-wave UV lights turn on a few seconds later, and “Christmas calcites” emit red, green, and orange. In the final cycle, both long- and short-wave lights turn on, and phosphorescent rocks glow with red, green, yellow, purple, and white.

The rocks glow when the UV light reacts with minerals like fluorite and calcite and excite activator elements inside the minerals. Atoms absorb some of that energy and release the rest as visible light.

With more than 300 specimens, the University’s fluorescent mineral collection is one of the largest in the country. Some minerals were donated by Lora Robins in 1977, with an additional donation from the Dulany Hunter Foundation and S. A. Dulany Hunter in 1982. Most of the fluorescent rocks originate from the Sterling Hill Mine in New Jersey.

“When the mines were being electrified so that they could work without headlamps, they brought in Thomas Edison’s company,” says David Hershey, assistant collections manager for University Museums. “They turned everything on and discovered the walls were just glowing.”

While the rocks can be a fun party trick, they also provide an opportunity to study the properties of phosphorescence and fluorescence, as well as mineral identification. Elizabeth Baughan, associate professor of classics and archaeology, brought one of her classes in after they unearthed pieces of glass during an archaeological dig on campus. They suspected the glass was fluorescent, and the UV lights proved their theory.

Area fourth graders are also frequent visitors to the gallery, as the rocks align with their Standards of Learning requirements. Heather Campbell, curator of museum programs, likes to watch excitement bloom when students recognize they’re not looking at a “boring, old rock.”

“When you do the whole light cycle, they realize that something mundane can be really cool and special,” she said.

“Right,” Hershey interjected, “you may not be looking at it in its best light.”

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Note: Due to COVID-19 and renovations in Boatwright Memorial Library, the Lora Robins Gallery will be closed to the public for the fall 2021 semester. Students, faculty, and staff may request a guided tour. A virtual tour of the exhibition Crystals: Minerals from the Collection is also available online.