Skip Maine state header navigation
Skip First Level Navigation | Skip All Navigation
|Home | Contact Us | Publications|
Chapter 3. Tips for Collecting Minerals
When visiting a collecting site, it is important to be safety conscious and help insure the goodwill of the property owner. Care should be taken to avoid falling into pits and shafts, or loosening boulders that may tumble onto people downslope from you. If you dig a deep hole in a mine dump, watch out that it does not cave in on you. Where possible, permission of the landowner should be obtained before entering a property, and trash should be packed out. Following these basic guidelines will help keep the collecting locations open for yourself and others. This is particularly important as housing developments and concerns about liability continue to close sites in New England.
A suitable assortment of tools is often essential for a successful mineral collecting trip. The minimum requirement is a good rock hammer, which can be purchased in hardware stores, mineral shops, or by mail. Better-grade hammers, such as those made by the Estwing Company, are preferred to the ones with wooden handles, since the heads tend to work loose on the latter type. A mason's hammer can be substituted if necessary. However, ordinary carpenters' hammers are too lightweight to effectively break rocks, and dangerous metal splinters may fly off the brittle heads. The larger crack hammers and sledge hammers, as well as chisels, are useful where specimens have to be broken from ledges or boulders.
Many collecting sites are in old quarries, where there are dumps consisting of piles of waste rock discarded during mining operations. Mineral specimens may be found by digging through these dumps with a shovel. The small, folding Army-type shovel is good for this purpose, and potato diggers are also helpful. Some collectors sift or wash the finer rock debris with a screen, especially when looking for pieces of tourmaline or amethyst. Other important accessories include a magnifying glass for checking small specimens, safety goggles or glasses for eye protection, and a knapsack with plenty of newspaper or other wrapping materials for transporting specimens. Industrious collectors may want to bring along wrecking bars, crowbars, jacks, and other heavy-duty equipment for moving boulders on mine dumps. The size of your tool kit will be determined partly by the walking distance to the locality, keeping in mind the additional weight of specimens on the return trip.
In addition to tools for collecting minerals, you will need food, drink, and other comfort items, especially for hikes to remote locations. Gloves are essential to help protect your hands from blisters and being cut by sharp quartz fragments, while band-aids and insect repellent may also be needed. Cameras are often overlooked when preparing for trips, but are vital for documenting mineral discoveries. Photos and videotapes may be used for giving talks or simply recalling details of past trips. In a few areas, it helps to bring a compass and pace counter (to keep track of how far you have walked) for navigating through the woods. Bright orange flagging tape is a handy trail marker when you want to relocate obscure localities. Also, GPS satellite receivers are very useful for woods navigation and recording the coordinates of collecting sites. Cell phones provide communication and safety back-up in areas where the signal is adequate.
Much could be written about the techniques of collecting minerals. An excellent book on this topic is Field Collecting Gemstones and Minerals, by Sinkankas (1988). This book covers all aspects of the subject, from the prospecting stage to cleaning, cataloging, and storing your specimens at home. Experience in the field will soon refine your collecting methods. At mines and quarries, most people choose to explore mine dumps rather than work the solid ledges. First scan the ground surface for anything special that may have been washed clean by the last rain. You may find satisfactory specimens right on top of the ground, but most of the better material will have been picked up by previous visitors. At pegmatite localities, look for fragments of beryl, lepidolite, or other signs of desirable mineralization when selecting a place to dig. A part of the dump that has not been dug over many times is likely to be more productive. This will sometimes be an area covered with bushes or small trees, necessitating the use of a saw or brush cutter where permissible. When digging in mine dumps, it will be easier to throw away the worthless rock and deepen your excavation if you begin on a sloping part of the dump surface. The rock debris often comes out dirty and must be carefully examined to spot crystals and other good specimens. If the dump material cannot be washed or screened, it will help to rake through it more than once before discarding. The collecting may get better or worse as you dig deeper, depending on where in the mine the debris was coming from as the dump was originally accumulated. If you find the better material to be concentrated in certain levels of the dump, this knowledge can guide further exploration.
You will probably want to reduce the size and weight of many specimens that you collect by removing excess matrix (host rock) surrounding the desired mineral. Trimming can also improve the balance of a specimen and make it easier to display in an attractive position. This procedure should be done very cautiously to avoid breaking crystals or popping them off the matrix. It will be most successful if there are favorably located fractures in the rock along which it will easily split, using a hammer and chisel. Best results are often obtained by placing the specimen on the ground to cushion the impact, and using the minimum required force. In extreme cases, trimming may need to be done at home with special equipment. Mistakes will inevitably be made, especially through the temptation to trim a piece more than it can withstand, but your skill will improve with practice.
Most mineral specimens, particularly those which are crystallized, should be carefully packed for the trip home. This can be done by wrapping them in layers of newspaper and snugly fitting them into a knapsack or other container. Sharp edges or corners on the matrix parts of specimens may need to be blunted with gentle hammer taps to prevent them from slicing through wrapping materials and damaging surrounding objects. Special care is advised for the packing of delicate specimens. Use soft wrapping materials, loosely wadded around fragile or projecting crystals, and place them on top of the container. Egg boxes, film canisters, and the like are useful for sorting and packing the smallest specimens. A well-labeled mineral is always more interesting and valuable to yourself and others. While you are still in the field, or soon after returning home, specimens ought to be labeled as to when and where they were collected. This information may be surprisingly hard to remember at a later date, especially after trips to other localities that produce similar minerals. You can clean most minerals found in Maine with soap and water, using a stiff brush to remove clinging dirt. Collectors use ultrasonic cleaners, acid baths, and many other methods for removing tenacious coatings such as rust stains. Some of these methods are potentially dangerous and must be learned with the help of reference books or experienced persons. The techniques for cleaning and cataloging minerals are beyond the scope of this guidebook, but Sinkankas (1988) and other authors discuss these subjects.
Collecting in the White Mountain National Forest
Several localities in this guidebook are situated on White Mountain National Forest (WMNF) property in western Maine. Visitors should be aware that sites in the WMNF are only open for noncommercial (hobby) collecting, which is limited to use of hand tools. Vehicles are not allowed on quarry access trails that lie within the WMNF. Mining and commercial mineral collecting on National Forest lands in general are under the jurisdiction of the U. S. Bureau of Land Management. A weekly or annual "passport" must be displayed on your vehicle while parked at certain places in the WMNF for mineral collecting or other recreational purposes. Questions regarding these regulations should be directed to: Androscoggin Ranger District, WMNF, 300 Glen Rd., Gorham, NH 03581. Phone: (603) 466-2713.
Sinkankas, J., 1988, Field collecting gemstones and minerals: Geoscience Press, 1040 Hyland Circle, Prescott, Arizona 86303, 397 p.
Last updated on October 6, 2005
|Copyright © 2005 All rights reserved.|