Spectacular 5-Color Rock from Franklin, New Jersey, Featuring Esperite, Calcite, Hardystonite, Wille
When it comes to fluorescent rocks, the brighter and more colors seen under UV, the better. Franklin, New Jersey, the Fluorescent Mineral Capital of the World, has unquestionably produced some of the brightest and best examples of multi-colored fluorescent rocks found anywhere. This rock is one such example. From the famous Parker Shaft at the Franklin mine, this spectacular rock shows the holy grail of fluorescent colors from this location. Under short wave UV the response is dominated by bright yellow fluorescing esperite, red fluorescent calcite and blue hardystonite. Minor amounts of willemite and clinohedrite provide green and orange fluorescent accents, respectively. This 5-color masterpiece of nature measures 4.2 x 2.7 x 2.2 inches, and weighs 1.33 pounds.
The photograph above shows the fluorescent response under short wave UV (254nm). See if you can count all 5 colors: 1.) Esperite = yellow; 2.) Calcite = red; 3.) Hardystonite = blue; 4.) Willemite = green; and 5.) Clinohedrite = orange.
As is the case with most fluorescent rocks, especially those from Franklin, New Jersey, they do not look very impressive under normal light, as seen above.