April 12 (Reuters) - Canada’s main stock index fell on Monday, weighed down by lower gold prices, while investors geared up for the start of the quarterly corporate earnings season. * At 9:35 a.m. ET (1335 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 45.22 points, or 0.24%, at 19,182.81. (Reporting by Sagarika Jaisinghani in Bengaluru; Editing by Shinjini Ganguli)