Kimberlite and microscopic diamond found in Montana

A mining official found kimberlite and preliminary test results yielded a microscopic diamond, The Associated Press reports.

If more diamonds are found at the 80-acre site known as the Homestead property, the land could become the state’s first-ever commercial diamond operation and the only working diamond mine in the United States, geologists reportedly said.

Canada currently has the only diamond mines operating in North America.

“It’s once in a lifetime. You just don’t find things like that every day,” Tom Charlton, an official with Delta Mining and Exploration Corp., told the AP. The Kentucky-based firm plans to begin large-scale exploration of the central Montana site next month.

What makes this latest discovery unique is it’s believed to be the first diamond ever found in Montana that was created here, rather than dropped in the state by a retreating glacier or other means. And accessibility makes the property so appealing, officials reportedly said.

Normally, it takes years to find underlying kimberlite deposits, let alone diamonds. But on the ranch site southeast of Lewistown, the kimberlite is exposed, pushed to the surface by high-speed gas millions of years ago, David W. Baker, an earth scientist who lives about 100 miles from the site, told the AP.

That accessibility, Charlton reportedly said, should cut excavation costs and lessen any damage to the prairie and the small, vacant cabin on the site.

Though rare, diamonds aren’t unheard of in Montana. Prospectors have plucked the gems from stream beds and glacial valleys for years — most notably the 14-carat Lewis and Clark diamond found at the base of a steep slope near Craig in 1990.

Delta Mining got permission from the landowner to explore the site several years ago. But the firm is only now getting together the estimated $700,000 needed for larger soil samples, Delta chief executive Barry Rayment reportedly said. More tests are planned in coming months.

Although the odds of a major find are stacked against them, Rayment reportedly said he believes the site, and possibly others in Montana, stand a good chance of producing commercial-grade diamonds.

Montana, Wyoming, and Colorado are all known to have the right kind of geology for diamonds. Northern Colorado was home to the country’s only working diamond mine, Kelsey Lake, until its closure several years ago because of legal troubles.

Delta Mining has rights to explore five other Montana properties totaling more than 7,500 acres, but is currently focusing on the Homestead property, which has the most potential, Rayment reportedly said.