Please send questions or comments to:
Franklin, NJ and the neighboring town of Ogdensburg, NJ are home to the world's most famous zinc mines. The Franklin ores are famous for mineral fluorescence, and for the large number of rare or unique mineral species. These zinc deposits have produced over 350 different mineral species.
In 1968 the State of New Jersey passed a resolution declaring the Borough of Franklin the "Fluorescent Mineral Capital of the World."
The mines at Franklin were worked for over 150 years, but were mined out by the mid-1950s. The Sterling Hill mine in Ogdensburg ceased production in 1986, but is now a wonderful museum of mining and mineralogy.
Many of the Franklin / Sterling Hill specimens are unimpressive under ordinary light. They show some amazing colors when exposed to short wave ultraviolet light! This fluorescence is what attracts so many collectors to the Franklin minerals.
The FRANKLIN GALLERY and STERLING HILL GALLERY include photos of my favorite specimens, identified by Mineral Name and (fluorescent color). Its a bit of irony* that the mineral named Franklinite is not fluorescent. Franklinite is seen as black crystals, grains, or bands found in most of the ore. Zincite is very rarely fluorescent; it is generally seen as red crystals, grains, bands, or plates in the ore. The third zinc ore mineral is Willemite, and comes in many colors and habits; from white to yellow, green, blue, brown, pink, red, purple, grey or even black; coarse to finely granular, prismatic crystals, in fibrous aggregates, botroydal, or massive. About the only reliable visual identifier is its characteristic bright green fluorescence under short wave UV light.
*bad mineralogy pun, since the iron in Franklinite quenches fluorescence.
If you prefer, you can view my favorites as a slide show in Flickr:
rocks & pipes
There are many very good web sites with detailed information on the New Jersey Zinc mines. They include museums, resources for educators, and lots of colorful photos of Franklin minerals:
Please send questions or comments to:
James A. Van Fleet
vanfleet@bucknell.edu
URL: http://www.facstaff.bucknell.edu/vanfleet/Franklin2.html
Updated: February 20, 2007
Portrait by John Van Fleet
artist for the Marvel Comics series Typhoid,
and DC Comics Batman: the Chalice
