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AGS / Geology / General Geology / Facts About Arkansas

Arkansas Bauxite

Bauxite - State Rock

This rock was formed by the weathering of nepheline syenite under tropical conditions, a process called laterization.  It is a type of lithified soil which is relatively low in silica and high in aluminum.  Bauxite was discovered in Arkansas before 1900 and was a major source of ore for aluminum metal for some 90 years in Saline and Pulaski Counties.  There are many uses for processed bauxite, aside from metal, including abrasives, cement, refractories, and chemicals.  Aluminum compounds are essential ingredients in many common household items, including deodorants, antacids, and paper.

History of Bauxite in Arkansas Pamphlet PDF

Arkansas Quartz

Quartz - State Mineral

Quartz is composed of oxygen and silica combined in a ratio of 2: 1. This mineral is hard, durable, weather-resistant, and relatively common.  Quartz crystals formed as hot waters percolated through fractured rock in the Ouachita Mountains some 245 million years ago.  Chemically pure sources of quartz are in much demand by industry as a source of the raw chemical feedstock for the manufacture of quartz wafers, silicon metal, glass, fused quartz, and optical fiber.  Arkansas has the most significant economically valuable deposits of high-quality quartz in the United States.

Arkansas Quartz Crystals Pamphlet PDF

Arkansas Diamond

Diamond - State Gem

Diamonds were first discovered in Arkansas in 1906.  Since that time over 100,000 diamonds have been recovered from the site now known as Crater of Diamonds State Park.  The average size recovered is about .21 carat.  Colors of the diamonds range from white to yellow and brown and the natural crystals are usually rounded.  The largest diamond found in Arkansas is The Uncle Sam, found in 1924.  This diamond weighed 40.24 carats.

Finding Diamonds in Arkansas Pamphlet PDF



Among the states, Arkansas Ranked (as of 2007):

Most current data for 2007, Arkansas Geological Survey, 2010

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Arkansas Geological Survey
Vardelle Parham Geology Center
3815 West Roosevelt Road
Little Rock, AR 72204
Phone: 501-296-1877 | Fax: 501-663-7360
Business Hours: Monday - Friday 8:00am - 4:30pm

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