Gold prices today tumbled to a 23-month low by losing Rs 1,150 to 25,650 Rs per 10 grams in the national capital on heavy selling by stockists and investors, triggered by a steep fall in overseas markets. All round selling by stockists on free-fall in overseas markets and investors shifting their funds to surging equities mainly pulled down the gold prices to a level last seen on August 9,2011. Silver also dropped by 1,490 Rs to trade below 40,000 at 39,010 Rs per kg on poor offtake by jewellers and coins makers.