U.S. gold coin sales surged this week as the anxiety over a euro-zone debt crisis spilled over into the United States and as Thursday’s sudden Wall Street collapse shook investors.

 The U.S. Mint sold gold coins this week at twice its normal pace, and a leading retailer said Thursday was a record day.

 Physical gold products such as coins and bars are traditionally a safe haven for anxious investors in times of economic and geopolitical crises. On Friday, U.S. stocks turned negative for the year on fears of another credit crisis.

Gold coin and bar dealers also said investors are turning to gold coins to protect their nest eggs from financial market turmoil.

 “Yesterday was our biggest day of the year in terms of investors buying gold,” said David Beahm, vice president of marketing at top U.S. retail gold coins dealer Blanchard & Co.  “There is no question that the meltdown in the paper assets yesterday was a huge case for diversification.”

 Beahm said he suggested investors buy more liquid one-ounce coins, particularly the American Eagles, South Africa’s Krugerrands, and the Canadian Maples Leaf gold coins.  “As long as it’s physical gold in your portfolio, you are protected,” he added.

 On Friday, the U.S. Mint said sales of the most popular American Eagle one-ounce gold coins totaled 41,500 ounces so far in the first week of May, compared to 60,500 ounces in the entire month of April.

 Investors also piled into gold exchange traded funds, which back their shares by buying physical bullion and keeping them in their vaults.

 Bullion holdings in the SPDR Gold Trust the world’s biggest gold ETF, said its holdings rose nearly 20 tonnes on Thursday, the biggest one-day gain since February 2009.

 (Reporting by Frank Tang; Editing by David Gregorio