MUMBAI (Reuters) - India hiked its gold import duty by 90 percent and doubled the tax on silver on Tuesday as the world's biggest consumer of bullion seeks to increase revenues, sending futures prices higher and hitting shares of jewellers. India changed the import duty on gold to 2 percent of value from the earlier flat 300 rupees per 10 grams and that of silver to 6 percent of value from 1,500 rupees per kilogram, the government said in a statement. Gold has soared this year, with international dollar prices touching a record of $1,920.30 per ounce in early September and Indian domestic prices hitting a peak in early December. The duty change would translate to about 570 rupees per 10 grams for gold, said Prithiviraj Kothari, president of the Bombay Bullion Association. The silver import duty could equate to 3,000 rupees per kg at current prices, he added. The BBA is sticking to its forecast for imports to fall 50 percent in January to March after they slipped about 8 per...