Elusive Multi-Wave UV Fluorescent Hardystonite, Franklin, New Jersey

The beautiful blue fluorescent mineral hardystonite is a favorite among collectors of specimens from Franklin, New Jersey. This mineral typically shows blue/purple-colored fluorescence under short wave UV, but little to no response under other wavelengths. In rare cases, hardystonite may also be fluorescent under mid and long wave UV, and this specimen provides an example of such material. This is a spectacular two-color rock that contains hardystonite and willemite from the Franklin Mine, Franklin, New Jersey. Under short wave UV the willemite fluoresces bright green and the hardystonite shows a typical deep blue response. Under mid and long wave UV however, the hardystonite shows a rare pale, lighter blue fluorescent response, and the willemite glows a more subdued green. The size of this specimen is 9.1 x 6.3 x 4.7 cm, and it weighs 481 grams.

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