An SEC filing showed that Warren Buffett's Berkshire Hathaway bought a stake in Barrick Gold in the second quarter.<br />Business Insider reports that Barrick Gold surged more than 10% in premarket trading Monday. <br />Berkshire Hathaway bought 21 million shares of the gold and copper miner.<br />The total stake in Barrick Gold was worth about $564 million, according to the Friday filing.<br />The buy comes as a bit of a surprise.<br />Buffett has been a critic of gold in the past, saying that it isn't as good of an investment as businesses, farms, and real estate.
