People have been finding loose diamonds across the United States and Canada since the early 1800s, but for the most part, no one knows where they came from. It was not until the 1990s that geologists tracked down the first commercial deposits, on the remote tundra of Canada’s Northwest Territories. Yaakov Weiss, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory, is investigating the origins of these rich diamond mines. He also hopes to explore the mysteries of the much rarer loose stones found in places like the U.S. Rockies and rural Arkansas. Will prospectors ever make a big strike closer to civilization? Here, a brief pictorial look at the history and science of North American diamonds. It is based on the book Barren Lands: An Epic Search for Diamonds in the North American Arctic. READ THE FULL SCIENTIFIC STORY
A heavily flawed half-carat diamond mined in the Northwest Territories, Canada, may hold chemical clues about why diamonds are found in farflung places across North America. (Yaakov Weiss)
Yaakov Weiss, a geochemist at Lamont-Doherty Earth Observatory, is looking for rare diamond samples from Arkansas and Colorado in order to compare with those from the far north. In his office, he inspects industrial-grade diamonds. (Kevin Krajick)
Gem-grade diamonds generally form beneath the world’s oldest rocks—the centers of ancient continents, called cratons (in red). The most productive cratons underlie Siberia, India, Africa, Australia and northern Canada. A few patches also occur in the American West. (Hugo Dummett)
Perhaps the original North American diamond prospector was Jacques Cartier, who sailed up the St. Lawrence River in the 1530s. In a cliff near what is now the city of Quebec, he found sparkly crystals–diamonds, he thought–and shipped them to the king of France. They turned out to be worthless quartz. (From H.P. Biggar, “The Voyages of Jacques Cartier”)
Eventually, a few real diamonds turned up. The earliest known were in the 1840s, when prospectors (here in a contemporary woodcut) in Georgia and neighboring states were sifting streambeds for gold flakes. (From “Minerals of Georgia,” Georgia Dept. of Natural Resources)
Soon, more accidental diamonds turned up across the United States, and later in southern Canada. Almost all were solitary finds, not commercial deposits. Far northern mines did not open until 1998. (From K. Krajick, “Barren Lands”)
During the 1849 California gold rush, prospectors scoured creekbeds for gold, and, occasionally spotted a diamond. This 1.95-carat stone was found by Burt Carpender of Smith Flat, Calif. (California Academy of Sciences)
Sometimes children at play have found diamonds. Stanley Devine of Oregon Township, Wisconsin (here as a grownup) was 5 years old in 1893 when he found a perfect 3.83-carat crystal while playing in a cornfield. His father quickly confiscated it in return for a penny, and sold it for $50. Devine is posing in the same spot 57 years later. (Wisconsin Geological & Natural History Survey archives)
Not all the finds were real. In 1872, conspirators planted $50,000 worth of industrial-grade South African diamonds and other imported gems on a desolate plateau in northern Colorado, then gathered gullible investors for their “mine.” These headlines were printed just before the so-called Great Diamond Hoax collapsed. Just like most modern financial scandals, no one went to jail, and the plotters kept much of the money. (From B. Woodard, “Diamonds in the Salt”)
In 1906, the closest thing to a working mine was discovered near Murfreesboro, Arkansas. A pig farmer named John Huddleston found diamonds in this field (shown here in the 1980s). It turned out to be underlain by a deposit of gem-bearing rock. But it was quickly worked out. Today it is a state park where visitors pay a fee to dig, and keep anything they find. Once in a while a valuable stone turns up. (Courtesy Crater of Diamonds State Park)
In the 20th century, scientists speculated that some diamonds of unknown origin had been carried from deposits in the far north by the great ice sheet that covered much of North America until about 15,000 years ago. The ice is outlined here in blue; pink dots are some of the chance finds. (Hugo Dummett)
In 1980s and 1990s, prospecting teams worked their way northward through remote terrains, including the Canadian Rockies, where this crew member was landed by helicopter. (Courtesy Paul Derkson)
The search led to the unpeopled tundra of Canada’s Northwest Territories, and the first profitable mines. The caribou stands by a giant boulder dropped by retreating glaciers. Glaciers also left trails of minerals from the deep earth, indicating that diamonds might lie nearby. (Kevin Krajick)
Canadian geologist Charles Fipke is usually credited as the driving force behind the far northern discoveries. Here, he pounds open a chunk of diamond ore found lying on the tundra’s surface. Right, Walter Nassichuk of the Geological Survey of Canada. (Kevin Krajick)
Start of the Ekati Diamond Mine, 1998. Eruptions of diamond-bearing rock formed craters that were later filled in by small lakes; miners drain the lakes, then dig straight down. The derricks in the middle are about three stories high. (Hugo Dummett)
Opening day, Ekati Diamond Mine, 1998. The gems in the case represent one day’s production, about a coffee can’s worth. Canada now supplies about 15 percent of the world gem market. (Kevin Krajick)
This truck hauls ore from the mine pit to a processing plant—244 tons at a pass. Because the climate is harsh and everything must be imported, far northern mines are extremely energy intensive. (Kevin Krajick)
Increased human use of resources—especially fossil fuels—is affecting the far north, mainly in the form of rapid warming. Here, in late spring a geophysicist dashes across a lake that in times past would have been solid ice. (Hugo Dummett)
Many miles east, in coastal Greenland, glacial ice is also receding, exposing ancient rocks previously inaccessible to geologists. Recently, prospectors here have found a few modest diamond deposits, and are on the trail for more. Human activity is transforming ever-more remote areas, both indirectly and directly. (Margie Turrin)
On Saturday, October 17, 2026 from 10am to 4pm, Lamont-Doherty Earth Observatory Open House—our biggest, best science fun and discovery event of the year—will take place on our beautiful campus in Palisades, NY. Mark your calendar and join us for this free, family-friendly celebration of science! RSVP Today!
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