Pop star Rihanna\'s \"Diamonds\" world concert tour is to kick off March 8 in Buffalo, N.Y., Live Nation said Friday. The tour is to begin March 8. It is scheduled to stop in more than 27 North American cities, including Los Angeles, Toronto, Boston, New York and Chicago, with additional dates to be announced soon. Tickets are to go on sale Sept. 14 at LiveNation.com. The Grammy Award winner\'s \"Loud\" concert tour grossed $90 million worldwide and was one of the highest grossing tours of 2011. She has sold more than 37 million albums and 146 million digital tracks.