Educational Publications
Minerals of the Washington, D.C. Area
1980, Bernstein, Lawrence R.
Educational Series 5
Scope of Report
This report covers approximately 14,500 square kilometers centered around Washington, D.C., with the region within a 50 kilometer radius of the city covered in most detail. The localities are divided into two broad categories: major localities and other localities. Major localities are those that were accessible at the time of writing, are of the greatest mineralogical interest, or are particularly representative of a certain type of deposit. The other localities are all additional locations of unusual minerals, including many that are no longer accessible. These are only given for the region of most detailed coverage. I have selected only those localities that contain unusual or well-crystallized minerals, and have made no attempt to include those quarries and other rock exposures that show no evidence of such material.
It is useful to remember that an increasingly large portion of the region around Washington is urban and suburban and subject to rapid changes in land use and ownership. This means thatroadcuts, mines, quarries, and other mineral exposures are rapidly and often permanently destroyed. Fortunately the reverse is also true, and new excavations, roadcuts, and quarries are continually being made and deserve attention.
With these facts in mind, I have put the localities in a geological perspective, giving them not as just isolated occurrences but showing how they fit into the geological context. With such information one can, for instance, predict that if gypsum crystals occur in a certain gray clay at one location, they are likely (though not certain) to occur in that same clay exposed somewhere else. This information is useful even if the original locality becomes inaccessible. In this sense, many of the localities should be considered mainly as clues to where similar material may turn up in the future.
Mineral Collecting
Before proceeding, a few aspects of mineral collecting in the region should be mentioned. First, it cannot be stressed too strongly that most of the localities given in this book are on private property and under no circumstances should collecting be done without the owner's permission. If permission is obtained, remember to leave the collecting area in as good condition as it was found, leaving no trash or large holes. In operating quarries one must always wear a hardhat, safety glasses, and hardtoed shoes, and be especially careful not to leave behind any metal equipment as this can damage the rock crushing machinery. Such conduct will hopefully keep the localities open to collectors and may even encourage the reopening of some locations that are now inaccessible.
Much public property is restricted for collecting, and none may be done within National Parks. Areas around reservoirs and many roadcuts also require special permission for mineral collecting, usually from a state or county agency.
It should also be remembered that during the summer, vegetation in the woods around Washington often takes on jungle-like aspects, making many localities essentially inaccessible. Also, summer is when poison ivy, poisonous snakes, mosquitoes, and gnats are at their peak, making early spring and late fall, or even winter if snow and ice are not prohibitive, the preferred seasons for collecting. By employing a good measure of common sense and courtesy, mineral collecting can continue to be an enjoyable and rewarding experience.
