After Thursday's frenzy, when counter-to-counter crowds surged in to buy precious metals, gold and silver buying and selling dropped off dramatically yesterday in the downtown office of Deak-Perera Exchange.

"It's only about 10 percent of Thursday's business," said Mike Zuras, a gold seller, peering across the tiny salesroom in which two prospective buyers waited.

In contrast, on Thursday Zuras had worked without stopping except for a 15 minute lunch-break and it wasn't "until 5 p.m. when you could see across the room," said Zuras.

The slowdown came at a time when gold and silver prices in international markets were fluctuating and falling off. It also came as would-be entrants into the gold and silver markets were discovering that cashing in old wedding rings doesn't pay the prices appearing in the newspapers for precious metals.

"We pay about $300 to $350 an ounce for 18 karat used jewelry," said Dennis Boone, manager of Boone and Sons Inc.'s downtown store. "It's not like if you had bullion or coins. Scrap gold has to be refined, and that's a long process that costs us money," he said.

Besides the cost of refining scrap gold, jewelry frequently contains less gold than the stamped value indicates, he said. Because the Federal Trade Commission allows some margin for variance from stamped value, jewelry stamped 18 karat may only be 16 karat, said Boone.

"We're not dealing with pure gold, we're dealing with alloys," he said.

Boone and Sons has been advertising for years that they buy jewelry, he said. In recent weeks, however, a growing number of customers have been walking in the door with jewelry to sell, he said. Boone estimated that 20 to 30 would-be sellers have been arriving daily at the downtown store recently.

"You've got to be fair when you give prices, but what's a fair price?" said Boone. Last summer, the going price for used silver was about $7.50 a penny-weight, in contrast to current values of $10 to $11, he said.

"Yesterday we could have given a lot more for gold and silver jewelry and been fair about it," he said. "It's up and down, up and down all the time."

Yesterday it was down, with the price of gold at closing time in New York at $603.10, down from $625 at closing the day before. Silver closed at $36.10, continuing a decline from $37.10.

Even with some signs that prices were headed down at least temporarily, there were still takers for silver dollars and gold krugerands at Deak's yesterday.

"Basically I'm just hoping it will increase," said a suburban woman who came downtown with her husband and daughter to buy four bars of silver.