Uncommon Brilliance

The Indian city of Surat, 250 kilometers north of Bombay, has the look of an industrial inferno. Textile mills belch smoke into Surat's discolored sky, mill workers live in dismal slums and homeless men nap alongside dogs on the railway-station floor. In 1994, the city achieved a moment of international fame when doctors announced pneumonic plague had resurfaced in its winding alleys. Nestled amid Surat's grime, however, is one of India's most extraordinary success stories. Whether you live in the U.S. or Japan, if you buy an engagement ring this year, there's a good chance you'll be taking home a diamond...