But after they processed 8,000 tons of rock, diamonds proved too rare to make the scheme profitable. The miners packed up their processing plant and shipped it to Canada. Their drilling cores, however, provided geologists with the first extensive maps of the diamond-bearing cone of lamproite rock. "Being a scientist, I wanted to have that information," says Howard. The surface area of the diamond field is 83 acres, and the cone funnels to a point some 700 feet below, making it the tenth-largest cone known in the world. Howard says it's shaped like a martini glass.
Arkansas diamonds originally formed more than three billion years ago under intense heat and pressure some 60 to 100 miles below the earth's surface. Then, about 100 million years ago, a giant gas bubble formed in the earth's roiling magma and shot up to the surface at 60 to 80 miles per hour, pulling diamonds and other material with it before launching into the air and raining debris back down. Some 60 to 80 percent of the diamonds forced to the surface were probably destroyed during this violent process. The park contains the largest cone, but five others—covering just a few acres each—are also in the area.
Though the diamonds could not support a commercial operation, there is still room for profit. Arkansas diamonds fetch about ten times more per carat than comparable stones, largely because collectors value the diamonds' American provenance and unique character. Many of the stones are smooth and rounded like a drop of glass, and they are among the hardest in the world. They come in three colors: white, yellow and brown. There's practically no other major mine in the world with stones that could pass for Arkansas natives, except maybe the Panna mines in India. (The similarity among the two sites' stones is likely to be skin-deep, says Howard, although no one has documented the trace elements that could be used to fingerprint Arkansas diamonds.) If Blake's 3.9-carat stone were an import, it wouldn't net more than several hundred dollars. The rest of his stones would fetch far less.
When park superintendent Stolarz saw Blake's diamond, he suggested Blake show it to Howard at the Arkansas Geological Survey. Howard was on vacation but made a special trip to his Little Rock office when he got the call about the big diamond. But Blake, who was driving back to Wisconsin with his fiancée and her daughter and sister, never showed up. Howard called Blake's cell phone again and again to no avail. He reached Blake a few days later, and Blake explained that he "had a flat tire and didn't have time to come by," Howard recalls.
A few weeks later, photographs of Blake's stones popped up on eBay and Blake's own Web site, Arkansas Diamond Jewelry.
When word of Blake's finds reached the Murfreesboro Miner's Camp, a trailer park and campground that hosts a population of good-natured diamond hunters, people were a tinge jealous. And suspicious. "I was like 'Jeez!'" says Denis Tyrell, 49-year-old licensed handyman who says he has made a living digging diamonds for the last 18 months. "You don't just come here, pick a spot, find 40 diamonds, and say 'I'll see you next year!'" It took Tyrell ten days to find his first diamond when he arrived at the park in June 2006. His personal best rate has been 38 diamonds in 31 days, a record he achieved in October 2008.
For all their suspicions, there was no evidence of wrongdoing. Then a fossil and mineral dealer named Yinan Wang noticed something strange. In September 2007, he had purchased one of Blake's smaller diamonds for $200. That December, Wang was interested in doing business with an Indian dealer named Malay Hirani. Wang asked Hirani to share a copy of a recent Kimberley Process Certificate, which would ensure that his rough diamonds were not the so-called blood diamonds traded by warlords in Africa and would verify that Hirani had previously done business in the United States. By chance, the certificate Hirani copied for Wang had come from an order Hirani had sent to Blake. Wang—simply sizing up his potential business partner—decided to ask Blake if Hirani was trustworthy. To his surprise, Blake denied the connection: All our diamonds are from the U.S., he said, according to Wang.
Wang didn't think much about the incident until March 2008. He was chatting with Hirani about sources for rough diamonds, and Wang mentioned Blake's Web site. The dealer looked at it and immediately thought he recognized some of Blake's jewels as his own. "I realized I had stumbled on something relatively big," Wang says. Hirani shared his receipts, shipping confirmation numbers, and photographs with Wang, and the duo later tracked the 3.9-carat diamond to another source, they say: a Belgian dealer named Philippe Klapholz. Tipped off by Wang, who was operating under the alias "Hal Guyot," the Web site Fakeminerals.com spelled out the alleged fraud.
If Blake really did plant foreign diamonds in Arkansas soil, was it a crime? Pike County Sheriff Preston Glenn is investigating Blake and expects to complete his work in early 2009, but says it would be up to the prosecuting attorney to determine what charges, if any, to pursue. In the meantime, officials say that Blake has agreed not to return to Crater of Diamonds State Park.
Blake says he has done nothing wrong and simply posted the wrong photos on his site. "A couple of diamonds were in question, but nobody has proven anything," he says.