A 5 per cent tumble in silver marked its biggest three-day loss in five years, and gold dragging with it as speculators continued to dump long positions after margins requirements were hiked early this week.
Spot silver dropped 4.9 per cent to $US39.58 an ounce having earlier hit a near one-month low at $US38.95.
Silver has now lost 20 per cent, the conventional criteria for a bear market, since it rallied to a record high near $US50 an ounce last Thursday.
Spot gold was down 1.6 per cent at $USUS1,515.30 an ounce, having hit a record $US1,575.79 on Monday.
Gold also notched its worst three-day decline since January despite a broad dollar drop and a ramping up of gold reserves by Mexico. Despite a sharp pullback, silver is still one of the top-performing commodities of the year with a 30 per cent gain.
But investors remained wary of a market in almost chronic surplus and a highly volatile price.
Sentiment among precious metals investors also took a hit after a report said high-profile investor George Soros, who was bullish on gold and a top investor in gold funds, has been selling gold and silver in the past month or so.
"With the CME raising three times in a week the margin requirement of silver, that was enough to disrupt the parabolic move in silver prices," said Mark Luschini, chief investment strategist of broker-dealer Janney Montgomery Scott, which manages $US53 billion in client assets.
Spot silver dropped 4.9 per cent to $US39.58 an ounce by 3:17 p.m. EDT (1917 GMT), having earlier hit a near one-month low at $US38.95.
Technicals were in focus after silver broke below its 20-day moving average on Tuesday, which had held since February. But prices were still well above the 100- and 200-day averages, after a 170 per cent rally over the last 12 months.
Silver's decline sent the gold/silver ratio to a three-week high near 40 from just below 32 last Thursday.
Spot gold was down 1.6 per cent at $US1,515.30 an ounce, having hit a record $US1,575.79 on Monday.
COMEX June gold futures settled down $US25.10, 1.6 per cent, at $US1,515.30. Gold futures volume topped 230,000 lots, one-third above its 250-day average.
Holdings of the largest gold-backed exchange-traded-fund (ETF), New York's SPDR Gold Trust, fell 0.4 per cent from Monday to Tuesday, while the largest silver-backed ETF, New York's iShares Silver Trust, fell about 1 per cent.
Also factoring into gold was news that George Soros' big $US28 billion firm and some hedge funds have been selling gold and silver, while other notable managers including John Paulson continued to favor precious metals, the Wall Street Journal reported, citing sources.
In the third quarter of 2010, Soros reduced some of his big bets on gold, a market he has called "the ultimate bubble."
The bullion market largely ignored news that Mexico's central bank has beefed up their bullion reserves by buying over 90 tonnes of gold, more than $US4 billion worth, over the past couple of years to put some of their massive foreign exchange holdings to work.
"The size (of the purchase) is certainly pretty chunky to have been accomplished in that space of time. So it certainly gives another sizable layer of support to gold's position in the international reserves system," said Credit Suisse precious metals analyst Tom Kendall.
Platinum fell 1.8 per cent to $US1819.74 an ounce, while palladium fell more than 5 per cent to $US742.05.
Reuters