A huge diamond unearthed in Botswana in April has been sold to French luxury fashion house Louis Vuitton for an undisclosed sum.The 1,758-carat stone is reportedly the second-largest found in a century.It has been named Sewelô meaning "rare find" in the Setswana language, and came from the Karowe mine in Letlhakane, central Botswana, which is owned by Lucara Diamond Corp.Louis Vuitton's decision to buy the diamond "signals the house’s growing ambitions in high-end jewellery," the Financial Times reports.