Matthew Hart has written splendid books on art theft, gold, and, most notably, diamonds. "The Russian Pink" is his first foray into fiction, a witty, high-octane international thriller with a plot as multifaceted as a Rubik's cube. Its theme can be put succinctly: "All diamonds are blood diamonds. It's just a question of whose blood."

At the book's center is Alex Turner, once a fence for diamond thieves, now an agent in the U.S. Treasury's Financial Crimes Enforcement Unit's Special Audits, an outfit whose mission is investigating money-laundering operations. When we first meet him, he is crouched in an NYPD surveillance vehicle watching a sting operation go bad in a church in Brighton Beach. A diamond is in play, as is a beautiful woman known as Slav Lily along with a number of Russian thugs, an inept federal agent, a knife-wielding Brazilian, a Glock 42 slimline subcompact, a Makarov semiautomatic, a Stechkin machine pistol, and a hapless priest just trying to say mass amid a shower of bullets.

Then matters become complicated. It's a presidential election year and the unpopular incumbent is in danger of losing the White House to a billionaire called Harry Nash. Alex's boss, Charles Chandler III, the fatuous scion of a depleted bloodline, would like him to dig up dirt on the man, specifically on the nature of his connection to a vicious diamond smuggler called Sergia Lime. A big clue to the men's relationship hangs around the neck of Nash's wife in the shape of a mesmerizing 464-carat pink diamond. Rumor says the stone once belonged to the Romanovs, thus its name: the Russian Pink. We, however, know better, having witnessed it being vacuumed up from the bed of the Chicapa River in Angola at the start of its deadly career in human affairs.

Alex is aided in his increasingly convoluted, ever more treacherous investigation by a motley assemblage of characters, among them, his colleague Tommy, a former football star who drives a Dakota Red 1957 Cadillac Eldorado at near Mach speed, and most crucially, Slav Lily, who, it emerges, is a double, possibly triple, agent with a terminal grudge against Lime.

Soon enough, Alex and Lily are flying off to Namaqualand in South Africa for a confrontation with a murderous Afrikaner and his goons. Then it's back again to New York, where all manner of ugly business is afoot, including threats to Alex's ex-wife and daughter.

Hart has all the tools for a writer of thrillers: wit, a knack for creating nearly unbearable suspense, and a light, unobtrusive touch in conveying information, in this case on diamonds — on the geological formations in which they are found, the ways they are processed, how they can be altered, and their use in criminal activities as "a kind of cash, except without serial numbers."

If we are lucky, Alex Turner will return, though right now he is in need of a rest.

Katherine A. Powers, a Minnesota native, also reviews for the Wall Street Journal and Washington Post.

The Russian Pink
By: Matthew Hart.
Publisher: Pegasus Crime, 272 pages, $25.95.