 Rough diamond in matrix
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Although diamonds are the most popular gemstone with United States consumers, domestic production of diamonds is very low. There is currently only one active diamond mine in the United States. This is at Crater of Diamonds State Park near Murfreesboro, Pike County,
Arkansas. There, recreational prospectors have been finding a few hundred carats of diamonds per year since the early 1970s. However, this is a tiny amount compared to the millions of carats of diamonds consumed per year.
Crater of Diamonds is a dig-for-fee operation maintained by the State of
Arkansas. The diamonds there are hosted in a lamproite breccia tuff and its overlying soil. Collectors pay a fee of a few dollars per day to prospect and can keep any diamonds that they find. This is the only diamond mine in the world that is open to the public. It has yielded a few significant finds: 1) the "Strawn-Wagner Diamond" - found at the Park as a 3.03 carat rough stone, it was cut to yield a 1.09 carat, "round brilliant" shape stone which received a perfect grading of 0/0/0 and stands as the most perfect diamond the American Gem Society has ever certified. 2) The "Uncle Sam" diamond, a 40.23 carat white diamond is the largest diamond ever found in North America.
At present, there are no commercial diamond mines operating in the United States. The Kelsey Lake Mine near the Colorado-Wyoming border was closed in April 2002. Estimated resources of the Kelsey Lake Mine at closure were about 17 million tons - containing approximately 4 carats of diamonds per 100 metric tons. About 50-65% of the diamonds produced at Kelsey Lake Mine were gem quality and almost one third of the gems produced were over one carat in size. The two most valuable stones reported to have been from the Kelsey Lake Mine were valued at $89,000 and $300,000.
There is good potential for commercial diamond production in the United States. Multiple diamond discoveries in Canada have prospectors looking at comparable areas in
Alaska and
Minnesota. More importantly, the Wyoming Geological Survey believes that a $1 billion diamond industry could develop in that state.
Wyoming has comparable conditions to the Canadian deposits and hundreds of kimberlite pipes are believed to exist. Twenty diamondiferous pipes have been discovered so far but assessment results have not been released to the public.
