New Mexico Mineral Symposium — Abstracts

The first diamonds were discovered near Murfreesboro, Pike County, Arkansas in 1906. Since then, there have been numerous attempts at commercial mining. All of these have been thwarted by a combination of factors: divided ownership, thievery, intense jealousy between owners, and possible interference from outside sources determined to block the successful exploitation of the diamonds.

The deposit was opened first as a tourist attraction in 1949 by one of the mine owners. It was acquired by the State of Arkansas in 1972 and since that time has been operated as Crater of Diamonds State Park. A nominal daily fee is charged, and finders are keepers of diamonds and other mineral and rock samples.

During the period 1972 to 1986, a total of 1,166,381 visitors found 10,719 diamonds, an average of one diamond for each 109 visitors. However, these figures are somewhat misleading because at least half of these diamonds were found by a few frequent visitors who have become very proficient. The only restrictions on collecting procedures, other than normal safety precautions, are that they involve no wheels or motors. Estimates of the total numbers of diamonds found since 1906 range as high as 400,000. One diamond-cutting firm in New York reportedly handled approximately 100,000 Arkansas diamonds over the years.

The largest and best-known diamond-bearing intrusive is the Prairie Creek pipe that crops out over approximately 73 acres, all within the state park. The diamondiferous rock is now called a lamproite breccia, in distinction to kimberlite breccia, and is similar to the rock type that is the source of the diamonds of western Australia. Famous diamonds from the deposit include the Uncle Sam (40.25 Ct), the Amarillo Starlight (16.37 Ct), the Star of Arkansas (15.33 Ct), and a magnificent, flawless, yellow crystal of 17.86 Ct now in the Roebling collection at the US National Museum.

Early in 1987 a bill was passed by the Arkansas State Legislature and signed by the governor authorizing a possible lease for commercial diamond mining within some part of the state park. Collecting by visitors to the park will continue, but possibly on a different basis.