Monday, June 29, 2009

Arkansas "Diamond"

A rough yellow Diamond from Arkansas
The Arkansas Legislature designated the Diamond as the official state gem in 1967, along with the Quartz crystal as the state mineral and Bauxite as the state rock. Arkansas is one of the few places in North America, other than Canada, where diamonds are present and currently the only place in the world where tourists may hunt for them. The importance of diamonds in Arkansas history is also acknowledged on the State Flag and the Arkansas state commemorative quarter issued in 2003.
Diamonds were discovered in Arkansas in 1906 near the mouth of Prairie Creek southeast of Murfreesboro, and later diamonds were reported from two small areas two miles northeast of the Prairie Creek pipe. The Crater of Diamonds volcanic pipe is part of a 95 million-year-old eroded volcano. The deeply sourced lamproite magma, from the upper mantle, brought the diamonds to the surface. The diamonds had crystallized in the cratonic root of the continent long before, and were sampled by the magma as it rose to the surface. This lamproite diamond source is unusual, as almost all diamonds are mined from kimberlite and from alluvial deposits of diamonds weathered from kimberlite. The only other prominent lamproite diamond source is the Argyle Diamond Mine in Australia. Although these discoveries in Arkansas created a modest local sensation, attempts to mine Arkansas diamonds commercially during the first half of the twentieth century were without sustained success. In the 1950s man-made diamonds suitable for industrial purposes were developed and sealed the fate on Arkansas' diamond mining prospects.
The failed commercial mining operations became a tourist attraction after World War II. The State of Arkansas bought the volcanic pipe property and some surrounding acreage for $750,000, which became the Crater of Diamonds State Park in 1972. The lure of finding gem-quality stones has drawn a steady flow of visitors to this unique attraction: nearly 2.3 million guests visited the park from 1972 to 2005. To aid the visitors in finding diamonds and other gemstones, the park plows up the fields several times a year to bring new lamporite to the surface. Park visitors find more than 600 diamonds each year of all colors and grades. Over 25,000 diamonds have been found in the crater since it became a state park. Visitors may keep any gemstone they find regardless of its value. In addition to diamonds, visitors may find semi-precious gems such as Amethyst, Agate, Apaptite, Jasper, Garnet, Quartz, Baryte, Fluorite, Calcite and some 40 other minerals. In nearby Hot Springs are located several Quartz mines, also open to the public for digging.