Gold prices slipped 230 rupees, to 20,400 rupees per ten grams at Delhi's bullion market, today, on heavy selling by stockists, triggered by negative global cues. Silver posted a sharp fall of 1,540 rupees, to 42,850 rupees per kilo. In New York, gold had dropped 25 dollars, to 1,346 dollars an ounce, yesterday. Silver lost 4.5 per cent, to 27.47 dollars an ounce