Supermarket giant Tesco has launched a service allowing customers to swap unwanted gold jewellery for cash. The retailer had trialled the scheme online and in about 15 stores from November. Shoppers are now able to post unwanted gold jewellery to designated stores. Tesco pledges on its website to pay £7.81 per gram of nine carat gold. The move marks a departure for the sale of scrap gold, usually a market dominated by pawnbrokers, with Tesco becoming one of the first mainstream retailers looking to profit from strong gold prices.