Collecting Fluorescent Minerals - The Basics, Where to Find Them, and How to Collect Them
Rock collecting is a pretty easy hobby to get into - buy a hammer, find a pile of rocks, and you're rock collecting. Fluorescent mineral collecting is a little more complicated. But folks are drawn to our hobby without even having learned how to collect white light rocks - the wondrous colors and glowing rocks draw folks like a moth to flame. This blog will attempt to guide folks new to the hobby who haven't had the benefit of collecting with experienced collectors in the selection of equipment, finding "glow spots and rocks", and ID'ing finds.
Your collecting style will probably determine the equipment and lights you will need - where and when will you be collecting? Fluorescent minerals are found almost anywhere there is a good selection of white light minerals. Mine dumps/tailing piles are obviously great candidates for any mineral, fluorescents included. Many abandoned mines and prospects offer good hunting, as well as remote areas with reports of an extensive assortment of minerals (such as Greenland). Unlike white light minerals, you will have to hunt for fluorescent minerals in the "dark" - either natural darkness or manmade. This means exploring at night, or carrying your own "darkness" with you.
Portable UV light - pretty much an absolute requirement. I know some people who can just about look at a rock and tell if it is fluorescent; not me. When I hike into an area to collect I want to be sure the rocks I carry out are good fluorescent specimens, so I always carry my light.
Flashlight - hunting at night? Rock piles, tailings, cliffs, forest trails - all very hard to navigate at night. Invest in a good headlamp (invaluable) and maybe even a white light flashlight.
Batteries - Your UV light needs power, lots of it. An average light is powered by 12vdc, and consumes 1 to 2 amps each hour. A 7 amp hour battery should last 3 to 6 hours. But keep an eye on weight; if you're hiking a long distance, up hills, etc. you might want to consider leaving the old lead-acid anchor at home and investing in a lightweight lithium battery pack.
Hammer and Chisel - odds are pretty good that you'll be scouring mine dumps that have been exposed to the weather for the last 100 years or more. The weathered exterior of a rock often reveals little about the fluorescence inside. You must be prepared to "crack that rock". Of course, any serious prospecting will require you to dig out veins, bust boulders, and apply serious strongarm methods - maybe even a sledgehammer will be useful. Some places might benefit from a prybar to dig rocks out of the pile/ground. I personally prefer a brick hammer that has a chisel side and a flat side, 4 to 6 lbs. Estwing makes some nice geological hammers - but pricey.
Goggles and Gloves - Hand-in-hand with the hammer to prevent rock chips taking out an eyeball. Plus - if you get the UV protection kind, they will double as eye protection when you get up close and personal with your UV light under a BBQ grill cover. A pair of good gloves would also be helpful.
Backpack - a good backpack will help you carry all this paraphernalia, and help lug your treasures back to the car.
Fluorescent Plastic Marking Tape - Called "Flagging Tape", great for marking areas you want to go back at night to explore. You've probably seen this kind of tape tied around trees in a nursery.
A couple of comments about safety are appropriate. Unlike ordinary rock collecting, fluorescent mineral collecting uses equipment which must be handled correctly, and we often find ourselves drawn to rocks which are uranyl activated. Both are subjects the first time collector should be aware of:
UV - Everyone knows that you should wear sunscreen at the beach; UV is harmful to the skin. Our mineral lights are extra powerful sources of UV. Common sense precautions should be used. Never look directly into a UV light with unprotected eyes, LW or SW. UV protection goggles are a really good idea. UV can reflect off rocks and bounce into your eyes causing "welder's burn" (flash burn). The result is usually a sandy feeling in the eyes - not fun. Learn more about the effects of UV on the skin and eyes in the GlowNotes post "The Photobiology of UV Damage to Skin". Most collectors rely on simple goggles for eye protection and, if their skin will be under UV for extended periods, perhaps gloves and long sleeves. Suntan lotion is another good protector.
Radioactivity - many of the green fluorescing rocks we collect are activated by the uranyl atom. Most are pretty harmless according to dosage charts illustrating microsieverts per day/year. For example, steenstrupine - a uranium crystal found in Greenland, is often less radioactive than your kitchen's granite countertop. For many years, "uranium glassware" was a popular dishware - we now collect it for the eerie green glow. But there are certainly some minerals that deserve our respect. Learn more about fluorescent minerals and radioactivity in the GlowNotes post "How Hot Are Your Rocks? Radioactivity in Uranyl-Activated Fluorescent Minerals".
The first expectation that newcomers have to the hobby is that they will be collecting at night. I have found that this often isn't the case. You will likely be exploring large piles of rocks, mine tailings, dumps, etc. - places you have not been to before. Many will be off-the-beaten-path, back in the woods, on the sides of mountains, edges of cliffs. These are not places to be wandering around at night, especially if you are not familiar with the topology.
I prefer visiting a locality when there is still daylight and perhaps, if safe, staying until darkness. That way I learn my way around in the daylight, and have a chance to look at the various minerals found in the area (in daylight). But more often than not I do my collecting in the daytime (or almost anytime in Greenland - land of the midnight sun). For this you need to bring your own darkness. The solution most folks opt for is a BBQ grill cover, medium size (custom fit for your size), and heavy enough to block the midday sun (thicker Weber covers work for me - just make sure it is fully opaque and doesn't have a white liner). Other options I have used include heavy duty plastic tarp (6 mil minimum), viewing boxes, or even a paint drop cloth. Whatever it is should be non-fluorescent and totally opaque (the sun is really bright, will shine through many cheap grill covers). Weight is an issue (that's why I like plastic) and keep in mind that a black grill cover doubles nicely as a sauna (bring plenty of water - you'll need it). (Hint: Don't forget to take off your sunglasses before diving under the grill cover!)
For some an ordinary longwave (LW) light might suffice (the Convoy 365nm flashlight is a great little light to carry everywhere you go). The problem with only a LW light is that you will miss many good fluorescent minerals. But the Convoy light is yielding some amazing results. It is so bright it can reveal fluorescence in minerals not previously known to be fluorescent under LW. For someone wanting to try out the hobby without investing the money for a SW light this might be a good choice.
A well-equipped FLM collector will carry a portable shortwave light (midwave really not necessary). A LW flashlight and a SW light will let you find just about any FLM; check it under MW when you get home - anything that glows under MW will also glow under LW or SW. Review the discussion about fluorescent mineral lights here to help you decide what kind of light you will be using. The brighter the better in my book, and I always worry about ruggedness and weight.
Where to find fluorescent minerals?
This is always the challenge. One of the best starting points is to join a club in your area and find out what collecting areas are around you. You may be the only serious fluorescent collector in the club but they'll at least be able to point out local mineral spots. Join the Fluorescent Mineral Group on Facebook - lots of folks from all over the world to help you with new collecting spots. Scour collecting web sites, trip reports, field trips, etc. Check Nature's Rainbows for minerals from your state (use the region's page).
Once you've identified a few spots do some research. Find the locality on Mindat.org and see if commonly fluorescent minerals are found from your proposed locality. Minerals such as calcite, fluorite, apatite, selenite, sphalerite, zircon, etc. all have a good chance of being fluorescent.
What kind of a mine was it? Scheelite, fluorite, or barite mines are hot contenders.
Are there dozens of minerals found at that locality? Odds are pretty good some of them will be fluorescent.
Uranium or REE mines are good prospects too.
The bottom line, fluorescent minerals are where you find them - they can be anywhere. Depending on where you live you may have to travel a bit, but it's worth the effort. You just have to light them up to find 'em! (But make sure you have permission to collect on private lands or restricted areas.)
The Art of Collecting
Nighttime collecting is the best. A moonless night, alone on a rock pile with only the glow of your UV light and hundreds of glowing embers at your feet - nothing could be better (or less likely).
I only know of a few of places in the world where that description is likely: the Buckwheat Dump in Franklin NJ, the mine dumps in Langban, Sweden, the Ilimaussaq Complex in Greenland (from 2am to 3am), and a few mines in Arizona. Each deposit is famous for almost every rock being fluorescent. But even in many of those places you won't find me scampering about on a moonless night - too easy to fall off a cliff, or break a leg. Most areas I have explored were mine dumps/tailing piles with rocks scattered everywhere, some half buried, others coated with eons of oxidation, moss, and dirt. But, since I did some research on the area, I know there is calcite (fluorite, sphalerite, wollastonite, glowrockite, ..., ...) and I want to find out if any of them are fluorescent. Keep in mind that calcite from one area might be very fluorescent, while from another area dead as a piece of coal.
My style is to visit the localities I think are most likely to produce magnificent fluorescent specimens and start cracking rock. I don't wait for darkness - too many reasons not to, as mentioned above. Further, I want to see (in daylight) what kind of rocks might be fluorescent. I pick a bunch of likely candidates, crack them open, and crawl under my grill cover to examine them up close and personal in the dark (this is where UV protection googles are useful - you'll find yourself putting the rock and lamp right up to your face). Soon I (hopefully) have a rough idea of what a fluorescent mineral from this locality looks like in the daylight. That's when I really get down to business.
Why is cracking rock so important to me? Check out this blog post - I find it critical to expose fresh faces on a rock.
Knowing what I'm looking for, I start gathering and cracking rock. It is so much easier to break rocks in daylight when you can see where your hammer is striking. Not important what each rock has inside - just that it has potential. The most commonly sought minerals for our UV displays are those with multiple colors. If your locality has several different types of FLM, odds are pretty good you'll find rocks with all of them on one face. But you'll have to crack a lot of rock, build a cache that you can easily sort through under the dreaded grill cover/sauna all at once. Even better, if you're comfortable navigating the area at night, build caches of split rock at several locations so you can return when it's dark to sort through them. And don't forget to mark veins, boulders, and other immovable objects for examination later in the dark. Try to knock a chip off big boulders to expose the innards, mark the location with fluorescent tape (the kind you get at Home Depot for marking trees or staked areas). That makes it real easy to find at night - just shine your UV light around and the tape will glow from hundreds of feet away. Mark your caches with the tape also...
Identifying Your Finds
This is where we have a leg up on our white light collector brethren. Purists will say the fluorescence is not an aid in identification but I disagree. Just the fact that a rock glows will eliminate many minerals. Fluorescent color right away gives a hint of the mineral ID: yellow makes one think of apatites, sphalerite, wollastonite. Red could be calcite, eucryptite, or feldspar. White could mean fluorite, calcite, selenite, or many other carbonates. Point being, fluorescent color helps point us in a direction where other means can narrow the ID to a few possibilities (cleavage, hardness, acid tests, etc. can then determine the final ID). And don't forget about phosphorescence - a very brief flash in a red fluorescent specimen might indicate manganese calcite. Cubic minerals that are phosphorescent are often fluorite. A bright yellow phosphorescence under LW is a good indicator of sphalerite.
Collecting fluorescent minerals is a fun and easy hobby. It's a great way to get out and enjoy nature and there's usually an adventure memory associated with each outing. Amateur collectors can make great finds using a UV light - no need to be able to identify some obscure mineral in the field with a loupe. If it glows brightly, it goes. Invest a few $$$ and c'mon over to the dark side - you'll be hooked on your first visit to a glow spot.
Happy Glow Hunting!
Comments from the FB Fluorescent Mineral Group
I posted this blog post to the FMS Fluorescent Mineral Group on Facebook soliciting comments. Good ones are posted below. Some comments were very general, relating to the text above. They were integrated into the post where appropriate.
The ignorance of a beginner in our hobby is truly bliss. We’re not encumbered by where we’re supposed to go and what we’re supposed to find. Hooked by a trip to Franklin, my daughter and I embarked on the hobby and picked up our first lamp. Our first trip was, to where else, our backyard. Sure enough, we found stuff that glowed. Bright greens of hyalite on decorative river rocks, red and white veins of calcite in random rocks my daughter had picked up on prior hikes, and a few other surprises. The next trip was to a local site known for fossils. At twilight, we turned on our lamp, and the ground glowed. Who knew that million years old shells glowed? I’ll never forget watching my 7-year-old daughter lug a five-pound rock off the hill and carry it for a quarter mile to the car. Over the last couple of years, we’ve explored a lot of local places for rocks: abandoned mines, road cuts, washes and gullies. We’ve found a lot of fluorescent rocks. Their overall quality doesn’t matter; it’s the hunt and the find that’s important. What’s great fun, though, is that we’ve actually found some really nice specimens in places that the “experts” had no idea held fluorescents. My thoughts are a little different than most. Experience and quality are irrelevant. Get out there, collect, and have fun. Eventually, even a blind squirrel finds a nut.
Good list! I'd humbly submit that with all our talk of Convoys (which I'm a fan of as well, now) I'd add that complete newbies may find that a better choice for longer ventures/night hikes. Not everyone can afford our typical lights or are willing to spend on them yet.
Mark great article!! Wish I had it a few years ago... comment so far, I prefer the lined grill cover, turning the white lining out helps to reflect the sun during the hot months. The lined ones seem more durable and the liner helps to cover those small cracks and holes that develop in the black material.