Stephen Bloom never outgrew his teenage fascination with pearls. Thanks to John Steinbeck's book "The Pearl" and his mother's special-occasion necklace, it grew in him the way a shard of coral grows in an oyster.

Now Bloom, a journalism professor at the University of Iowa, has poured his passion into "Tears of Mermaids: The Secret Story of Pearls" (St. Martin's Press, 382 pages, $27.99), a tell-all book about pearls and the network that delivers them to the world's well-dressed women. The more we learn, the more contagious his passion becomes.

Pearls are a paradox, he writes, representing both chastity and sexuality, humility and conceit, Michelle Obama and Paris Hilton. Bloom also was drawn to another paradox: the fortune spent on producing and dealing pearls and the pittance spent on the people who do the diving and processing.

Bloom spent four years and traveled more than 30,000 miles from oyster beds in the South Seas to the auction houses of New York City. He met the "pearl lords" in Japan, Australia and the Philippines. He visited oyster farms in China and Tahiti. He worked as a deck hand on a pearling ship.

He introduces characters worthy of a screenplay -- the swaggering Australian pearl lord, the Chinese "pearler" in her Cadillac and sprayed-on jeans, and the improbable "Rana of Fresno," whose home in a modest subdivision is a treasure chest of rare pearls.

He takes us to the auction of a strand of rare natural pearls once owned by Minnesota railroad baron James J. Hill.

Bloom finally did get to talk to women who make up most of the pearl industry's workforce, women who would never wear the pearls they sorted in smelly shacks and assembly lines. Did they care? Their answers are a surprising coda to a fascinating book.

Maureen McCarthy is the Topics team leader at the Star Tribune.