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Show SALT FLAT NEWS JANUARY 1971 il jr: v Reprinted from the Deseret Sampler, September 25, 1970 A '. W- M : A"-- w.jJL . Pirates of long ago were notorious for their famous maps that inevitably led them to the spot marked X, the location of their buried treasure. Modern-da- y Dugway pirates do not have to find a deserted island, or pace of 50 steps, or find a rock in the shape of a skull to locate their hidden - HOW TO FIND A GEODE ''iff silican--bearin- to Utah constantly over is the geode a spherically-shape- d rock that reveals an agate lining and quartz crystals when the specimen is cut in two. Geodes are also sometimes known as modules. However, the term geodes is more proper if the form has a hollow center. Solid geodes should be called nodules. The term thunder-eg- g is also in common usage in the Northwest. GEODES are not common to the Dugway area alone. They can be found in different parts of the United States and the world, but they all vary in inside design and composition. For example, the Dugway geode is known for its superb variety of quartz crystals and is considered by many to be the most spectacular variety of the more than 200 varieties and forms of quartz known. Brazil is noted for its beautiful amethyst crystal-line- d geodes. Oregon for solid deep blue agate-fille- d nodules, and Iowa for THE DUGWAY geode searchneed only to follow a simple map to lead them to the location of the famed geode beds which are approximately 30 to 35 miles from Dugway. The digging area is mainly concentrated some five miles northwest of the Dug-- . way Pass and may be reached from the East by traveling on the Simpson Spring-Calla-o Road (the old Pony Express and Overland Stage route) to Dugway Pass, a prominent landmark in Juab County. Approximately 4.2 miles West from the crest of Dugway Pass, a samll jeep trail leads northward from the Simpson Spring-Calla- o Road to the main collecting area. Geodes occur throughout the entire area. Some very successful collecting trips have resulted when groups have begun digging in new locations within this area. A few years ago geodes, which had been brought to the surface through the elements of weathering, could be found lying upon the surface but now one must labor to find them. The geodes are from six inches to six feet deep, and possibly deeper beneath the surface. MOST OF the material surrounding the geodes is usually sand and gravel, disintegrated rhyolite, clay, or even a mixture of all three. The three main digging tools include'a short handled shovel, a pick type rock hammer, and a short handled pick which has a point- - on one side and a scoop on the other. Successful safaris to the geode area may render one to two hundred pounds of geodes in a day; however, more often approximately ten pounds would be an average amount. Thus, the Dugway geode pirates must merely set their sails West, follow the map carefully, and listen for the familiar cry, Thars geodes in them thar ers and-ah- hs calcite crystal-line- d geodes. Oil in the have been found geodes of Niota, Illinois, which vicinity in addition to crystals have been found to contain up to one quart of viscous bitumen oil. The origin of these geodes is another unsolved mystery of the earths geology. The formation of goedes still remains as one of natures most unusual phenomenons surrounding volcanic activity. The Dugway geodes were most likely formed during the middle Terrtiary Period approximately 40 million years ago when lava flows were common in the Utah area. Many of the flows in the area produced add type lava flows which upon cooling created rhyolite rock Rhyolite has the greatest silict -- hills!!! . s . v?"' vTSSaA--- , i h As" ' 'V , naturally become ideal reservoirs for the channeling of solutions to percolate through the "cracks into the hollow center, depositing silica, the constituent of quartz. The silica is in the form of silica dioxide more commonly known as. quartz. The quartz solutions then flow throughout the cracks seeking a place to deposit the quartz and the inner One of the most spectacular sights and souvenirs that a visitor tf688UrGS OGDEN v' - oohs- - ; . I ' g cavity walls prove to be the ideal location. There, the quartz is deposited in layers as agate. This process is not continuous and it varies in intensity and degree of . . purity of the quartz solution. THE DIFFERENT layers of banded agate is ample evidence of the various impurities within the quartz solution and of the interruption of the depositing process. Also, many colors in the agate banding results when a slight change of minerals within the solution occurs. A pure solution of quartz could form glass dear quartz crystals upon the agate bands. The rhyolite lava rock is also altered to a slight degree during this process with the absorption of quartz along the outer faces of the cavity. This makes the stone stronger than the rhyolite matrix surrounding the geode, and thus makes it more resistant to erosion and disintegration. Therefore, the rhyolite which surrounds the geode eventually erodes away and the geode is then freed from its former rhyolite captor. The majority of the geodes discovered at the Dugway location do vary widely from place to place. Some are solid agate (modules), some are filled with quartz crystal up to one-hal- f long, some have amethyst crystals, some have bands of agate and crystals, while some even content of the normally encountered lavas. ASSOCIATED with many lava flows are gas or steam cavities (called vugs) resulting from large amounts of water vapor, carbon dioxide, and other gases present in the molten rode. With the cooling of the lava, cavities remained in the rhyolite. This is the first stage in the geode formation. When the lava begins the cooling process, cracks begin to shrinks appear as the rhyolite and cracks. These ' cracks then NEWS Photo by R. Monztos A typical Geode hunter. with a diamond blade saw along the longitudinal axis to obtain two matched halves. The saw marks are then removed, preferably, on a lapidary wheel using 220 mesh abrasive grit. When the saw marks are re- to due calcareous the probably are on found which moved, additional grinding is coatings and the not many geodes, quartz necessary with finer grits such as 302 before polishing with a or rhyolite. oxide on a felt wheel1. .tin size about from in They vary one-hal- f inch to ovr three feat Persons desiring more informain diameter. The spherical shape tion on geodes please contact Charles Helm, President Dugway has seams or striations on its outer surface somewhat like the Gem and Mineral Society, Dugway, Utah. stitching on a baseball. The Dugway geode can be cut have a solid center composed of a common type opal. MOST OF the Dugway geodes fluoresce a green and yellow color under the short or long wave ultraviolet light. This is Mileage Points DUGWAY. RANGE WENbOVER o SALT LAKE CITY Barry PROVO To Callao Dry River Fish Springs 4-- t Tooaz- - DugwayWeN This area greatly enlarged I THOMAS RANGE maps not to scale |
