What does a scientist do at a former zinc mine in the hills of northwest New Jersey? That’s what we decided to ask geologist Dr. Earl Verbeek. Here are our questions and what he had to say about his work.

What do you do at the Sterling Hill Mining Museum?

Like most folks at this museum my job seems to change daily. During much of the school year I am one of the tour guides who take people into the mine and show them how mining was done here. When there’s time I also do some geological research. Our mine is a wonderfully complex bit of geology, and much more remains to be learned about it than is known thus far.

My principal job, though, is to expand the educational program of our museum. We’re very busy these days developing workshops, courses, and evening lectures for teachers, students, and the public. We emphasize the physical rather than the biological sciences, but if you like bats and snakes, well, we’ve got them too.

Our growing collections of fluorescent minerals, ore minerals, and rocks also demand a lot of my time. Every specimen acquired by the museum has to be cleaned, labeled, and described in a computerized catalogue. This is a never-ending task, but a most enjoyable one.

What does a geologist do?

Just as there are many different types of doctors, there are different types of geologists. Some spend their careers outdoors, mapping and studying the different rock types to understand an area’s geological evolution. Others are laboratory people who use a wide variety of analytical instruments to extract a surprising amount of information from a rock or mineral or fossil. There are petroleum geologists, mine geologists, exploration geologists, paleontologists (geologists who study fossils), environmental geologists, marine geologists, and many more. Depending on where they are, geologists travel by foot, horse, car, ship, helicopter, you name it. It’s an occupation that can get you just about anywhere, doing just about anything.

For most of us, however, the final product of our work is a written report. If you don’t enjoy writing, this may not be the profession for you.

Did you like to collect rocks and minerals when you were a kid?

Yes, very much. I grew up in Philadelphia and started collecting rocks when I was five. My father had been trained as a furniture maker, and I used to ruin his hammers until finally, in desperation, he bought me one of my own. I still have it, by the way—a stone mason’s hammer, which worked quite well until the handle broke.

What kind of work did you do before you came to Sterling Hill?

Like most folks I’ve had a series of jobs over the years. I started my career as a research geologist with the U.S. Geological Survey in Denver. I was a structural geologist then. Have you ever seen deformed rocks—rocks with layers folded into fantastic shapes, or rocks that have been broken in many directions? Those are the things that a structural geologist studies. This part of my career lasted 20 years but came to an abrupt end when the U.S. Geological Survey lost one-third of its work force in 1995.

After that I worked as a mine reclamation inspector for the U.S. Bureau of Land Management in Nevada. Because mining commonly involves building roads, digging out the ore, and other activities that alter the landscape, it’s important that mining companies restore the land to its original condition after they’re done extracting the ore. That’s called reclamation—reclaiming the land. My job for two years was to inspect reclaimed land to see how well the reclamation was done and how well new vegetation was taking hold in areas that had been dug into.

During my third year with the BLM I became an environmental specialist. We had a little office in Tonopah, Nevada, and we were in charge of managing 6.1 million acres of public land. That’s more than the entire state of New Jersey! I loved this job because we had to manage so many different uses of the land—mining, grazing, hiking, timbering, off-road vehicle use, on and on. Those were good years.

In 1998 I retired from the BLM and came back East to live. I taught earth science at a local high school for one year but didn’t like it. For three years after that I worked for a county government in Pennsylvania. Here was another fascinating job! Anytime anyone wanted to build something in the county, whether it was a house, an office, a cell tower, or a store, the plans had to be submitted to our office for comment. My job was to look at how the new construction might result in pollution. Water running off a large parking lot, for example, commonly washes oil, transmission fluid, tire dust, and other pollutants directly into nearby streams. If enough pollution of this type occurs you will quickly see a change in the stream wildlife.

What got you interested in geology?

I can’t remember not being interested in geology. Even as a toddler I was picking up rocks and studying them. What really got me hooked, though, was a display of fluorescent minerals at the Academy of Natural Sciences in Philadelphia. I went there when I was eight, and never again was there much doubt as to what I’d choose for a career.

It helped that my parents were supportive of my interest. They took me to meetings of the Philadelphia Mineralogical Society, purchased books for me, and drove me to collecting sites I had learned about from those books. Though they had little interest in rocks and minerals themselves, they worked hard to keep my scientific curiosity satisfied, and I’m sure that’s why I was so confident of what I was going to do as an adult. My parents even let me take over a spare kitchen in our house and convert it into a chemical laboratory.

Why do you like being a geologist?

The Earth fascinates me. Whenever I accompanied my parents on a drive I’d see different rocks from place to place and wonder how they got there. The more I learned about rocks and minerals the more fascinated I became—so many processes had gone into their formation, so many things had happened to the rocks, that I just had to study them to understand them better.

I became a geologist for another reason, too—the opportunity to work outdoors. When I was young the physical demands of the job appealed to me, because doing geological field work is an excellent way to keep in shape. I used to feel sorry for my friends who had to join health clubs to get the exercise they needed. I was getting paid to exercise on the job!

Then there’s the spirit of adventure, for most field geologists travel quite a bit. I liked the idea of traveling to places that few people select as vacation destinations, and hiking to places that no one had visited in decades, or perhaps ever. Not all of these places were pretty or appealing—some were downright awful—but all of them were interesting. My last reason is perhaps the most important of all. Geology, like all science, offers the prospect of discovery, of learning something that no one else ever knew before. That’s exciting to me. The combination of being paid to discover something with the opportunity to publish my findings was irresistible.

What are your favorite places for geology?

There’s no easy answer to this one! Let me mention just three places from a long, long list.

Iceland: Iceland is a wonderful place to study volcanoes. Iceland sits right on the Mid-Atlantic Ridge, which means it is being torn apart by sea-floor spreading. There are some wonderful rift valleys in the western part of Iceland that record this process.

Arches National Park, Utah: I love the bizarre landscape here, with its soaring rock arches, pinnacles, fins, alcoves, and mazes of small canyons. The red rock and green vegetation set against the deep blue sky are simply incredible.

Yellowstone National Park, Wyoming: Who can resist bubbling mud pots, deep thermal pools, geysers spurting water high into the air, and sulfurous fumes drifting on the breeze? This is geology in action. I love the days when the park is enveloped in deep fog, so you can’t see anything until you’re almost on top of it—but you can hear the workings of the Earth all around you.

Where are some good places to collect fluorescent minerals?

Any place rock is exposed is a good place to try. Fluorescent minerals are found in all kinds of rock—igneous, metamorphic, and sedimentary—and the best thing to do is simply go out and look. Even if you live in a flat, glaciated area, you may still find road cuts, gravel pits, and excavations for buildings where chunks of rock included in the glacial debris are exposed. Some astonishingly fine fluorescent specimens have come from such areas.

Good specimens of fluorescent minerals have been found in every state of the Union. Some states, however, are considerably more blessed with fluorescent minerals than others. New Jersey, for example, has produced many tons of spectacular fluorescent minerals from the zinc mines at Franklin and Sterling Hill. California and Arizona have also furnished a wealth of very fine specimens. Much more doubtless remains to be discovered—only a tiny percentage of the outdoors has been inspected with a portable ultraviolet lamp at night.

When exploring for minerals, how do you know if they’ll fluoresce or not?

You don’t. That doesn’t mean there aren’t guidelines, though. For example, any mineral that looks like a metal almost certainly will not fluoresce. Neither will many dark-colored minerals, regardless of whether they look metallic or not. Minerals that contain iron, copper, cobalt, or nickel are unlikely to fluoresce too. The best candidates for fluorescence are light-colored minerals that look glassy, waxy, or dull rather than metallic. Experienced collectors use these clues, and others like them, to decide on promising places to look for fluorescent minerals.

Are fluorescent minerals expensive?

Some are, yes, but many are not, so having little money to spend shouldn’t discourage you from collecting fluorescent minerals. Some minerals are expensive because they are rare, or exceptionally beautiful, or occur in large, lustrous crystals, but fluorescent minerals often look quite ordinary in daylight. Many visitors to our museum remark on this and say things like “These look like they came from my driveway.”

If you did nothing more than purchase chunks of the most common mineral species you can still build a wonderfully attractive collection of fluorescent minerals. Many specimens can be had for less than you might spend on a meal at a fast-food restaurant. However, if you have lots of money and like to spend it, you can do that too, on the rarer and more fabulous specimens. Some specimens sell for thousands of dollars each!

Expensive or not, remember that you can always collect your own fluorescent minerals for free. This is often more enjoyable than buying them, and if you have duplicates of minerals that are common in your area you can trade with other collectors for minerals you can’t collect locally.

What can you do with a fluorescent mineral?

Besides enjoying its beauty, you mean? Well, for one thing you could have a little fun with your friends. If, for example, you had a piece of brown willemite from our mine here at Sterling Hill, you could bet your friends that you can change the brown mineral into a green one without touching the mineral at all. Then just switch off the room lights and hold an ultraviolet lamp over the specimen. Presto! Green!

People have done all kinds of strange things with fluorescent minerals over the years. A few people have built fireplaces with them, or used cut slabs of fluorescent minerals on the tops of their coffee tables or as borders around their swimming pools. Ordinarily this is done only with the more common fluorescent minerals, and one should never use a fine specimen for such purposes. Other people have crushed fluorescent minerals to a powder and used them to make clever paintings. One such painting is dubbed the “Crow-cus” and shows a crow in daylight, but a crocus under ultraviolet light.

Most collectors, though, simply arrange their fluorescent minerals on shelves in a bookcase or a closet, or build a custom display case for them, and show them to their friends whenever they visit. One collector described such displays as being like “fireworks frozen in the dark.”

How can I start collecting fluorescent minerals?

There are two general approaches: collect your own minerals, or purchase them from mineral dealers. To collect your own, first you’ll need an ultraviolet lamp. Probably there is a store, museum, or scientific supply house that sells them within reasonable driving distance, or you can order one through the Internet. A good lamp can be expensive, but it will last you a lifetime. Be sure to get one with a battery pack if you want to hunt for your own specimens outdoors. For likely places to look, consult a local mineral club.

Fluorescent minerals are widely available at rock shows and over the Internet. Rock shows can be a great deal of fun, but remember that many dealers do not sort their minerals for fluorescence, so you may have to take an ultraviolet lamp and a “blackout” cloth with you to view mineral fluorescence in daylight.

A list of dealers in fluorescent minerals, compiled by the Fluorescent Mineral Society, can be viewed by clicking here. You should also consider joining this society if you find you like collecting and studying fluorescent minerals.

Are minerals the only things that fluoresce?

Not at all. You’ll find many things around your house that fluoresce too. Try using an ultraviolet light on the glasses and plates in your kitchen, on the clothes in your bedroom, and on various items of plastic throughout the house. You’ll discover that a lot of things fluoresce, sometimes in colors quite different from those they have in daylight. Many liquids fluoresce too, including some sodas, tonic water, and milk. And don’t forget your vegetables! See how many fluorescent foods you can find—the results might surprise you.

If you have a shortwave ultraviolet lamp, though, please remember that this can quickly result in painfully sunburned eyes if you look into it. For the same reason please make sure never to point any ultraviolet light at your pets.

What was mined at Sterling Hill?

For part of the 19th century the south end of the orebody at Sterling Hill was mined for iron. The ore contained a little manganese, too, and this made the iron smelted from the ore a superior metal for tools and farm implements. Later, from the 1860s to 1986, Sterling Hill was mined exclusively for zinc ore. The mine ultimately produced about 11 million tons of zinc ore at an average grade of 20-22% zinc. By any standard, Sterling Hill was a world-class zinc deposit. Incidentally, there is a lot of ore left underground here; not all of it was mined.

Do you like it inside the mine?

Yes, very much, particularly in summer. I know students like summer because they’re off from school, but to me summer means heat, insects, traffic, noise, and construction delays. The mine, in contrast, is blessedly cool, free of pesty insects, and peaceful. Even better, though, is the opportunity to be inside the rocks of the Earth, to see and study them in three dimensions, and thus to understand them in a more intimate way than can be done in a laboratory.

Are there bats in the mine?

Yes—and we like them. Bats are among nature’s most misunderstood creatures, and I suppose their appearance doesn’t help people like them very much. When you think of how many insects a typical bat eats on a summer night, though, you’ll quickly come to value their presence.

We used to have thousands of bats in the upper levels of the mine, but they left as the mine gradually filled with water after the zinc company left and turned off the pumps. Now all but the highest level is flooded, and few bats are left. I used to like seeing them flutter through the light of my cap lamp underground.

Do you still do mining there?

On a small scale, yes. We have more than 35,000 visitors a year, and nearly all of them take a tour through the mine and get a free sample of fluorescent zinc ore to take home. Now think about how big a pile of 35,000 rocks might be, even if they were fairly small rocks, and you’ll see that we have to keep mining if we’re going to keep on giving away these souvenirs. We don’t use any explosives, though, because the local residents wouldn’t like it.

We also do local mining to uncover new minerals for scientific purposes and for sale to collectors. The Sterling Hill mine, and the Franklin mine two miles to the north, are world-famous mineral deposits. More than 360 different mineral species have been found here. That’s a world record, so you can understand why so many people collect the local minerals, and why we continue to mine them. Just recently a mineral new to the area was discovered at Sterling Hill.