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: What is Selenite?, Wildlife Associated with Crystal Digging, Observation Tower, Crystal Digging.The Salt Plains are a flat expanse of mud, completely devoid of vegetation, located in north central Oklahoma. The name, Salt Plains, is derived from the thin layer of salt that covers the flats. This salt was used by Native American tribes and early pioneers who first settled the area.
The plains are 7 miles in length and approximately 3 miles wide and lie within the boundaries of the Salt Plains National Wildlife Refuge. The plains border the Great Salt Plains Reservoir, constructed by the U.S. Army Corps of Engineers in 1941.
Selenite is a crystallized form of gypsum. Chemically, it is a hydrous calcium sulfate. Gypsum is a common mineral that takes on a great variety of crystal forms and shapes. On the Salt Plains, the crystals are formed just below the salt encrusted surface. They are seldom found deeper than 2 feet below the surface.
Crystals take on the characteristics of their environment; the finer the soil, the more clear the crystals. Iron oxide in the soil gives the crystals their chocolate brown color. Because these crystals form in wet soil, sand and clay particles are included within the crystal. These particles often form an "hourglass" shape, found only in this area. Other foreign objects in the soil, such as sticks, rocks, bones, and even cockleburs, are sometimes included as the crystal forms.
Single crystals, penetration twins, and clusters are the typical crystal shapes most frequently encountered on the refuge. Exceptional individual crystals measuring up to 7 inches long have been found, along with complex combinations weighing as much as 38 pounds.
In certain places on the Salt Plains, gypsum and saline solutions in the soil are sufficiently concentrated to promote crystal growth. When temperature and brine conditions are ideal, the crystals may form very rapidly. When heavy rains or floods bring great quantities of freshwater to the plains, some of the selenite crystals may go back into solution until conditions are right for recrystallization.
As long as nothing happens to change the mineral content of the waters draining into the Salt Plains, these crystals will continue to form, just as they do today.
The most productive area in which the selenite crystals are found has been divided into sections. Each section is used on a rotating basis to allow time for crystal growth replacement. It is also important to restrict crystal digging to particular sections because many bird species use the area for nesting purposes. Among these species are threatened snowy plovers, endangered interior least terns, and American avocets.
Snowy plovers can be found throughout the crystal digging area. Interior least terns and American avocets are mostly seen along the stream. It is important that these birds not be disturbed. Furthermore, it is illegal to harass or destroy the bird's eggs and nests.
For the pleasure of viewing wildlife, an observation tower is located at the entrance of the selenite crystal digging area. The tower is open year round from sunrise to sunset. During fall months, white pelicans and sandhill cranes can be seen in the area, also an occasional whooping crane may be sighted. In winter, several thousand geese can often be seen along the lake shoreline.
Crystal digging is permitted April 1 through October 15, sunrise to sunset.
No special permit is required. Collectors are permitted to remove up to 10 pounds of crystals plus one large cluster for their personal use in any one day.
Once in the digging area, please drive your car only on the prescribed lanes of travel.
Due to the white salt surface, it is easy to get sunburned. Sunglasses and protective clothing are recommended.
A map is available from refuge headquarters that shows the area selenite crystals are found, along with the roads leading to the area. Caution: Driving a car upon the plains can be hazardous. Beneath the surface crust, which is comparatively shallow, lies a quagmire of quicksand. For this reason, visitors are permitted to drive only on the prescribed route.
The gate leading into the crystal digging area, is located six miles west of Jet, Oklahoma, on U.S. Highway 64, then north on a dirt road for three miles, then east one mile to the gate.
The visitor coming from Cherokee, Oklahoma, can reach the gate by going 3 miles south from Fifth Street in Cherokee on U.S. Highway 64, and then 5 miles east on a paved road to the gate.
Crystal digging will be confined to areas posted for such activity.
We are pleased to have you as guests on the Salt Plains Selenite Crystal Digging Area.
Enjoy your visit.
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http://sturgeon.irm.r2.fws.gov/u2/refuges/oklahoma/selenite.html - revised April 15, 2002
KEYWORDS=selenite, crystals, digging, recreation, Oklahoma, refuge