Spot gold prices slipped below the $4,000 per ounce after a significant increase this year, dipping 2.7 per cent from last week to $3,984.43 an ounce, data showed on Monday. The price of 10 grams of 24-carat gold was Rs 1,21,113 during the day trade, according to data published by the India Bullion and Jewellers Association (IBJA).