It’s early January, and Eira Thomas is steering her 2003 Porsche Carrera 4 through Vancouver’s Stanley Park, which looks as if it’s been ravaged by a hurricane. The city is being raked by its 14th storm since November, and has lost about 10,000 trees to high winds. A caller on Thomas’ cell phone warns her that a causeway leading out of the city will soon close. She snaps the phone shut and drops the Porsche into third gear. She’s soon flying over the bridge.

Thomas has never been one to be put off by inclement weather. The daughter of a Welsh mining engineer who toted her along in the field as a child, she grew up with mining in her blood and mud on her boots. And in 1994, 180 miles northeast of Yellowknife in Canada’s remote Northwest Territories—a latitudinal notch from the Arctic Circle—she led the field team that discovered a multibillion-dollar diamond deposit known as Diavik.

In the 13 years since, Thomas has evolved from a poster girl for Canadian diamond exploration into a boardroom brawler, one who recently triumphed in a three-way, $120 million merger that was one part friendly, one part hostile. Tall and fit, with alabaster skin and flowing red hair, Eira Thomas has become, in the eyes of many, the ideal mining company C.E.O.—an agile mix of scientist, strategic thinker, and promoter.

Her company, Stornoway Diamond, is still small in comparison with industry giants like De Beers, BHP Billiton, and Rio Tinto. But it is well positioned to become a big-league player at a time of consolidation in the industry. Thomas’ goal: to reprise her monumental diamond strike by combing an astonishing 22 million acres under lease. Thomas is out to prove that she is not just the luckiest woman in the world but that she remains a diamond explorer to bet on.

Since the December 2006 release of Blood Diamond, the latest Hollywood blockbuster with a social conscience, consumers have been wringing their hands over whether their diamond purchases are financing rebel armies in Sierra Leone. The Leonardo DiCaprio vehicle tackles important issues, but many in the industry say that so-called blood, or conflict, diamonds are an old story. And in a sense, they are. Though working conditions in the continent’s diamond fields remain well below first-world standards, there are no active conflicts being funded by the illicit sale of diamonds in Africa today.

The industry would prefer to concentrate on its feel-good story of the decade: Canada, which went from being a nonfactor to the third-largest supplier of rough diamonds in 2003, contributing some 13 percent of a worldwide total of $9.24 billion. In 2006, according to WWW International Diamond Consultants Ltd., Canada produced $1.2 billion worth of rough diamonds; its ranking, however, had slipped to fifth. 

Until the 1990s, North America was jokingly referred to as a good place to sell diamonds but a bad place to find them. So wrote Matthew Hart in Diamond: A Journey to the Heart of an Obsession. All that changed when explorers Charles Fipke and Stewart Blusson sent a shock wave through the diamond world with the 1991 announcement of a diamond find at Point Lake, north of Lac de Gras, in Canada’s Northwest Territories. Further discoveries by Fipke would ultimately turn into the Ekati diamond mine, Canada’s first, and would make Fipke and Blusson very, very rich. Canadian Business magazine pegs Fipke’s net worth at $445 million and Blusson’s at $573 million. The finds would also set off a staking frenzy not seen since the Klondike gold rush in the Yukon Territory.

Enter Eira’s father, Grenville Thomas, a colorful mining engineer with a thick Welsh brogue. Grenville emigrated to Canada in 1964 and found work at a nickel mine in Sudbury, Ontario. He soon found his way to Yellowknife, and was well known among Canadian gold miners by the 1990s. After Fipke’s diamond discovery, Grenville quickly began staking ground east and southeast of Fipke’s dig for his own company, Aber Resources. Grenville admits that he relied on a strategy he jokingly insists is a bona fide mining term: closeology. In a staking rush, he explains, you look for ground as close to the discovery as you can get. “Forget all the other ‘ologies’—geology, biology, and the like,” he says. “Mines tend to be close together. That’s closeology.”