Gold tumbled to three-month low on stronger USD and as market sentiment was affected by the Italian auction due later today. Spot gold lost 0.7% to USD1,543.79 an ounce, indicating 11% monthly decline in December, the biggest monthly decrease in the last three years. US gold eased down by 1.2% to USD1,545. The yellow metal may fall to USD1,542 an ounce during today's trading, reported Wang Tao, analysts from Reuters.