The fluorescence of these minerals was not known to most; in fact, seeing the fluorescence requires a special short-wave ultraviolet light emitter. Fluorite, which is prevalent in this particular dig done in Amity, actually has exceptional fluorescing ability. The term "fluorescence" originates from a discovery by George Gabriel Stokes in 1852. He observed that fluorite emitted a blue glow when illuminated with visible light "beyond the violet end of the spectrum." Fluorite can fluoresce if held in sunlight then moved into the shade where noticeable color change can be seen . Fluorite emits a blue-violet color under short wave and long wave light.
Only about 15% of all minerals noticeably fluoresce. Fluorescence occurs when impurities known as activators exist. The crystalline structure of some minerals cause them to glow. Crystals temporarily absorb a small amount of light and an instant later release a small amount of it in a different wavelength. The ultraviolet light cast by short wave emitters, 100-280 nm, accentuates light released by these crystals. Novelty black lights are actually long wave emitters, 315-400 nm, and, therefore, are ineffective for revealing mineral fluorescence.
|Normal light, crystals under a short wave ultraviolet light, and under long wave ultraviolet light. The short wave light reveals the brilliant colored light emitted by these crystals.|
|Amity Minerals: Spinel bearing marble finds bearing rare Warwickite, Edenite and Clintonite dating to Grenville Age discovered here 1828-32.|
|A specimen label for some Clintonite collected from Amity in the Town of Warwick, NY.|
|A sample of the many specimens collected during the 19th century from Amity, Monroe and the surrounding area for the Ecole des Mines in France.|
|In this May/June issue of Rocks & Minerals magazine there is a feature story on New York State crystals in the Ecole de Mines collection in France.|
|A pit dug by Glenn Rhein with an excavator brought many important crystal finds to light.|
|An example of a giant diopside crystal in situ after excavation on the Amity property.|
The estimate on the age of this crystals is somewhere in the 800 million years ago range, according to Glenn, who has been a quick study of a collection that most mineralogist would take a lifetime to acquire. The crystals may have been formed when our local Mount Adam and Eve, composed of granite, pushed through an existing marble belt forming the kind of stuff you find in plentitude in Franklin. As Glenn went through a litany of identifications of these samples including "Augite, Phlogopite..." and the like, I realized all the homework I had if some of this find were to come to be on display at Museum Village.
In addition to being a visual sensation of perfect tetrahedrons and octahedrons in natural light, many of these crystals fluoresce under a black light. There were some that glowed shades of blue and green, but the real show stopper was the hand size rock that lit up hot pink! There's a real wow factor with these minerals that Museum Village would be remiss in not presenting for its school visitors. The fact that has often been shared with me is that Orange County is a geologists' treasure trove yet the largest collection of rocks and minerals from this area is actually at the Ecole des Mines in Paris, France. Recently, Glenn and his wife Karen travelled to Paris to present some samples from their recent finds in Amity to the School of Mines, and they have been extremely generous with donations to a number of universities and museums across the country.
In the coming months, the museum plans to receive some specimens from the "Rhein vein" thanks to the generosity of Glenn and Karen, including some crystals that fluoresce, and both Glenn and George Gordianos have discussed with us the possibility of realizing a dark room within the Natural History Building at the museum that will provide an unforgettable experience for visitors of these natural wonders. We hope to have that in place by the Spring 2012 season.
|Meionite & Diopside|