Tiffany buys most of its gold from a Utah mine called Bingham Canyon that does not use cyanide, which can pollute water and lead to the release of other pollutants like mercury. Last year Tiffany began processing its gold itself at a plant in Rhode Island as part of a strategy to control the supply chain. Tiffany aims ultimately to provide customers with a "chain of custody assurance" stating where the gold in a ring or necklace has been, from mine to display case.

These changes are partly coming about, people in and out of the jewelry industry say, because gold mining's environmental and social impacts have become impossible to ignore, especially in developing countries where political protests, corruption and displacement of indigenous peoples have often accompanied mining.

Because most of the known gold deposits in the world are in microscopic form -- the shiny nuggets of old are as dated as the miner and his mule -- huge industrial open-pit mines, usually using cyanide to retrieve the metal from base rock, are required to make mining economically viable. And because the grades of ore are so weak, the process is hugely destructive and wasteful, with at least 30 tons of waste rock often needed to produce a single gold ring.

A months-long investigation by The New York Times, which led to a four-part series last year called "The Cost of Gold," also raised questions about how and whether communities in developing countries consent to the mines in their midst, and whether the long-term environmental impacts in places like Nevada and Indonesia are being correctly assessed.

Then there's the Wal-Mart effect.

Wal-Mart's strategy for everything it sells, including gold, is to eliminate the middleman, buy direct from suppliers and pass the savings on to customers. Jewelers are following suit as they try to cut costs and compete. Industry experts and executives say the trend has nothing to do with ethics, but that more control of supply makes the ethics debate over dirty gold somewhat easier, because companies are already thinking more deeply about where things come from.

"The overall theme is know your vendors," said David H. Sternblitz, a vice president and the treasurer at Zale Corporation. "Make sure you know who you're dealing with."