KINSHASA, Congo -- A U.N.-backed body assigned to curb the sale of conflict diamonds suspended the Republic of Congo from the legitimate diamond trade on accusations the African nation sent millions of dollars in smuggled gems onto the world market. The suspension followed a May 31-June 4 mission to Republic of Congo that found the country was dealing in millions of carats of smuggled diamonds from other African countries. The West African country was sending the gems through the lesser diamond centers of Switzerland and the United Arab Emirates to avoid rigorous controls at the world's diamond hub, Antwerp, Belgium,...