Gold struck another historic peak of 18,000 rupees per ten gram in the national capital on Wednesday on sustained buying by stockists for the current marriage season amid a weakening dollar.The yellow metal spurted by 220 rupees to 18,000 rupees per ten gram, a level never seen before, on seasonal buying and as prices in international markets touched record levels with the dollar extending its losses. Traders said a weak dollar made the precious metal cheaper for buyers using stronger currencies. Gold hit 1,180.20 dollars an ounce in trading on the London Bullion Market. The gold has rallied 11 per cent after India bought 200 metric tons of gold from the International Monetary Fund in October. Mauritius, Sri Lanka and Russia have followed suit since then.