Gold declined for a fourth day in London and entered a so-called bear market as concern Greece will have to leave the euro boosted the dollar and cut the metal's appeal as an alternative asset.

The US Dollar Index, a measure against six major counterparts, rose a 13th day to a four-month high after Greece's political leaders failed to form a ruling coalition. Bullion slid as much as 21 percent from its intraday record in September, the common definition of a bear market. On a closing basis, the metal needs to settle at $1,520.18 an ounce to record a 20 percent drop from its September peak.

"It's a risk-off environment," Peter Hickson, head of commodities research at UBS AG, said in Hong Kong. "People are concerned about liquidity and they're going to take security in the US dollar."