Franklin, Fluorescent Mineral Capital of the World
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FRANKLIN, FLUORESCENT MINERAL CAPITAL OF THE WORLD © Spex Industries, Inc. 1981 by R.W. )ones, Jr. 3520 N. Rose Circle Dr., Scottsdale, AZ 85251 Tell people that Franklin, New Jersey is lots. In the hustle and bustle of their daily The deposit has yielded close to 300 noted throughout the world for its myriad lives, people tend to forget New Jersey's different minerals, a number vastly fluorescent minerals and your reward is natural endowments: the rich farmlands greater than from any other known source likely to be a blank stare. Tell them that of the south, t he rolling forest and grazing in the world. More amazing, nearly 60 of Franklin, along with neighboring Ogdens lands of the northwest, the manicured these minerals exhibit luminescence, in burg, is the home of a truly unique metal lawns and rich green golf courses of its the form of almost instantaneous fluores deposit and boredom sets in for sure. But suburbs, and the unique zinc-manganese- cence or as days long persistent take them for a walk on a dark night iron deposits of Franklin and Sterling Hill phosphorescence. across the waste rock dumps atop this ore Maybe for two or three weeks of t he deposit and they begin to act strangely. su mmer people forego the turmoil and The luminescence of many Frankl in Like children in a candy shop, they're cavort on ocean beaches or bask in the species explains the strange behavior intrigued, captivated by the multi-hued glory of a sun-dappled lake. But to accept noted among miners and mineral colors of these chameleon rocks. Drab the ex istence in New jersey of one of the collectors over the years. It is reliably looking by daylight, they burst into color world's mineralogical wonders tests their reported. for insta nc e, that in the 1940s, as under ultraviolet light. Among the brilliant credulity. miners watched the broken ore coming reds and greens, an occasional rock will into the mill, it was not unusual for one of f lash a bright yellow, or a soft brown, or Yet they are intrigued by those glowing them to grab a chunk and dash off to the lush purple, or fiery orange. And if you're rocks. They want to know how they got nearest dark telephone booth where really lucky, a rock will respond with there and why we dig them. W hat they fluorescent response might be evoked tches of three or four colors, calcite, learn is a story even more incredible than with a hand-held lamp. Decades earlier, workers might have been observed \ .. 11lemite, hardystonite, and cl inohedrite the glowing colors. competing for your attention. Willemite swinging a flashing, smoking, noisy Franklin and Ogdensburg(Sterling Hill will even f luoresce with an ethereal glow machine over a jiggling table covered with mine) are neighboring towns nestled in the in sunlight. a watery flow of crushed ore. Their jobs rolling hills of northwest New Jersey. Each were to monitor the separation of ore from Although the night walk gets people's is situated next to a zinc-iron-manganese waste rock as the table vibrated throwing attention instantly, they still find it hard to ore deposit the likes of which exist the tailings as ide. Their machine was an accept that such an intriguing occurrence nowhere else in the world. Sc ientists sti ll iron spark gap whch incidentally emitted takes place in New Jersey, not in some far argue over whether these two deposits are weak ultraviolet. away exotic land. To most of us New one - now separated by natural forces - Jersey conjures up fog-bound turnpikes or two which developed under similar This early application of ultraviolet radia and speeding cars, gambling casinos and conditions over a billion years ago. For tion was successful because the main neon lights, oil refineries and endless rows convenience I normally think of them as waste rock of the deposit is calcite rich in of factories with their clogged parking one. manganese which causes it to f luoresce a Massive wollastonite separated from calcite by a Veins of green fluorescing willemite, Zn2Si04, in Fibrous radiating aggregates of wollastonite band of feldspar. Rarity and beauty are combined red fluorescing calcite, CaC03• Numberless vivid against a background of fluorescent calcite. This in this showpiece from "The Fluorescent Mineral and intriguing patterns of these two minerals have form of wollastonite appears to be restricted to Capital of the World." been found throughout the ores at Franklin and Franklin. Sterling Hill. -1- bright red. Also, one of the major zinc oxides as well as many trace elements. representative of a locality or type of ores, willemite, fluoresces bright green, Together t hey form end less complex occurrence; he knew the subtleties of activated by its manganese content. species and varieties. crystal habit, color, association and size that distinguish a fine specimen from a Novice visitors may still observe strange Exactly how many minerals occur here is good one; he was a keen judge of the doings at Frank lin or Sterling Hill. I recall an open, controversial subject. The factors that determine the aesthetic and my own first visit to the famous October 1980 program for the 24th Annual scientif ic va lues and, of course, he was Buckwheat Dump in Franklin. I was Franklin-Sterling Mineral Exhibit master at that virtually lost art, sight startled to see a rumpled, hunching dome (sponsored by the Kiwanis Club of identification." Since Palache's death in of blanket being propelled by some Franklin) listed 281 names, about five of 1954, dozens of other investigators, unseen force over the dump. It paused which still appear in doubt. But surely professional as well as amateurs, have and the sound of hammering started. The there will be others not yet announced to taken up the torch in the ongoing search hammering stopped and the blanket take thei r place. In fact, just as we go to for new minerals. moved on. The " force" turned out to be a press Pete J. Dunn of the Smithsonian collector with his ultravio let lamp and Institute announced the most recent find, Most of the current work on new minerals hammer seeking fluorescent riches cast sterlinghillite. So rare that but a single is from old specimens. The reason is that aside by earlier mining! Night collecting is specimen has been located, the mineral is the Franklin mine was closed in 1954 and a common sight here. Col lectors look like a hydrated manganese arsenate. It was mining is on the wane at Sterling Hill, large violet-hued fireflies as they hover found in 0.1 mm clusters of micron-sized productivity probably limited to less than over the rock piles which are being crystals, requiring the powerful analytical a decade henc e. depleted rapidly of fluorescent minerals capabilities of an electron probe for the by this collecting process. unambiguous characterization that resu lts Yet, as mining activity wanes, research in acceptance by the International activity waxes strong. One noted observer The vast variety of Franklin mineral Mineralogical Association. has pointed out, for example, t hat "of 24 species suggests that within these ore species unique to the area, nine have been bodies will be found further evidence of At the rate new minerals are being found in the last six years, six of the nine in discovered in this mineralogical soup, t he their uniqueness. Frondel (1972), as an the last three years." Indeed, a number of total may one day hit 300 species and example, pointed out that the pyroxenes t hese species have been named in honor varieties. But because of the pers istent amphiboles, and micas (a ll particularly o f some of the many amateur mineral arguments about just what constitutes a difficult to identify anyway) associated collectors who have fallen in love with the variety, we' ll let you count for yourself with these zinc ores contain unusually place and whose impact on the study of (Table 1). high amounts of manganese and zinc, Franklin and Sterling Hill has been while the feldspars are rich in barium and The exceptionally large number of mineral considerab le. Recently discovered species lead. That old bug-a-boo of "what species identified at Franklin/Sterling Hill named after contributing amateurs are: constitutes a variety" owes much of its should be credited to the diligence of hauckite after Richard Hauck, diligent confusion to such complex it ies. sc ientific investigators who are constantly collector and student of the deposi t; dismembering anything unusual, wherever kolicite after John Kolic, Sterling H ill Composition of the Zinc Ores discovered. Extensive crystallographic work miner and collector; gerstmannite after The Franklin and Sterling Hill deposit on Franklin minerals was started by Ewald Gerstmann, who assem bled the ( comprises three primary ores: franklinite Charles Palache, professor of Mineralogy noteworthy mineral collection now 2 2 3 3 (Zn, Mn+ , Fe+ )(Fe + , Mn+ h04; at Harvard University. In 1904 he began administered by SPEX Industries; kraisslite willemite (Zn2Si04); and zincite (Zn, collecting minerals from Franklin and over after Dr. and Mrs. Fred Kraiss l, whose Mn)O. These are interspersed in a ubiqui the next 30 years systematically studied studies and financial support at Franklin tous matrix of calcite (CaC0 3) that itself them. His resea rch culminated in a have been instrumental in preserv ing this fluoresces a beautiful red. Willemite, first comprehensive book published by the mineral wealth; and marsturite after reported from Franklin in 1824, does occur U.S. Geological Survey in 1935 Marion Stuart, a strong supporter of as a minor ore elsewhere.