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This classic Franklin piece containing bright blue hardystonite, bright green willemite and minor red/orange calcite on one side from the historic Franklin Mine in Franklin, Sussex County, New Jersey, from the collection of noted fluorescent-mineral collector and researcher Richard C. Bostwick. Hardystonite is a calcium-zinc silicate and a particularly significant Franklin mineral. Franklin, New Jersey is the type locality for hardystonite, and the mineral is famous among fluorescent mineral collectors for its characteristic bright and deep blue fluorescence under shortwave ultraviolet light. FOMS notes that hardystonite occurred extensively within the Franklin orebody but was not found at neighboring Sterling Hill. The specimen also shows fluorescence under longwave UV, although the shortwave response is considerably more dramatic. Multi-wavelength response in Franklin hardystonite can vary substantially from specimen to specimen; particularly responsive material can show visible blue fluorescence beyond shortwave UV.
Ex. Richard C. Bostwick Collection.
This specimen originates from the renowned collection of Richard C. “Dick” Bostwick, one of the foremost authorities and collectors of fluorescent minerals from Franklin and Sterling Hill, New Jersey.
Beginning his collection in 1960, Bostwick devoted more than six decades to studying, documenting, and preserving the extraordinary fluorescent mineralogy of this historic mining district. His connection to Sterling Hill extended underground. Bostwick worked at the Sterling Hill Mine during the 1970s, giving him firsthand access to and knowledge of the mines.
Over his lifetime, Bostwick assembled what has been recognized as the world’s largest reference collection of fluorescent minerals from Franklin and Sterling Hill. His contributions to the field were ultimately honored with induction into the Fluorescent Mineral Society Hall of Fame, and the rare Franklin mineral bostwickite was named in recognition of his contributions.
They were nicknamed "Yooperlites" which is derived from the name “yooper”. A yooper is a nickname for the Upper Peninsula natives and these fluorescent stones quickly gained fame. After data was published on these fluorescent stones, it was discovered that sodalite is the actual true mineral that is fluorescing orange.
365nm UV light is often called "blacklight". Before the advent of longwave UV LEDs, blacklight fluorescent tubes, (the kinds used in hippie days to light up psychedelic posters) were the standard longwave UV light for our hobby. They were not very powerful but they did light a large area.
Enter 365nm UV LEDs
First, an animation showing the difference between the UV flashlight we recommend (365nm filtered UV flashlight) versus unfiltered 395nm UV flashlights we see many folks carrying around at shows. So. much. visible purple light. We selected a bunch of rocks as a demonstration. Took pictures of them under his flashlight without the filter and then with the filter.
