In New Jersey, The Sterling Hill Mining Museum is famous for its variety of immersive and educational exhibits, and massive collection of fluorescent minerals. The fluorescent exhibits are displayed along the walls of Rainbow tunnel that was excavated in 1990, are lined with rare minerals that glow bright green and red under ultraviolet light. The museum was originally an old zinc mine, having opened in 1739. It is one of oldest mine in the country, when it was closed in 1986. However, it was bought by Richard and Robert Hauck and unveiled as a museum in 1990. The ore that was mined here was wonderfully rich in content, averaging more than 20 % zinc, and occurred in thick seams that went to a depth of over 2,550 feet below the surface through tunnels totaling more than 35 miles in length.
Moreover, Sterling Hill is the treasure chest of minerals; more than 350 different mineral species have been found here a world record for such a small area. Though, over two dozen of these have been found nowhere else on Earth. The Sterling Hill is close to Franklin Mine, 2.5 miles to the north, equally famous for its fluorescent minerals. Almost 90 different mineral species have been documented as fluorescent. The Sterling Hill Mine, is also known as Sterling Hill Mine Tour & Museum of Fluorescence, is a former iron and zinc mine was added to the National Register of Historic Places on 1991. Well, it took almost 30 minutes inside the Exhibit hall, containing a wide variety of mining memorabilia, mineralogical samples, fossils, and meteorites. The mine is also home to the Ellis Astronomical Observatory, the Thomas S. Warren Museum of Fluorescence, and a collection of mining equipment.
Here questions come in mind, what causes fluorescence in minerals. All minerals have the ability to reflect light, makes them visible to the human eye. However, few minerals have an exciting physical property recognized as "fluorescence". Therefore, these minerals have the ability to provisionally absorb a small amount of light and an instant later release a small amount of light of a different wavelength. This change in wavelength causes a temporary color change of the mineral in the eye of a human observer. The fluorescent mineral color change is most remarkable when they are illuminated in darkness by ultraviolet light not visible to humans and they release visible light, and about 15 percent of minerals are fluorescent. The museum periodically arranges public mineral collecting sessions as well as more private and behind the scene events for local geology clubs.