This Woman Just Doubled Her Worth ... to $20B

Smart Company has been keeping an eye on Australian mining magnate Gina Rinehart, and it predicted last year that she might well end up being the world's richest person someday. If she keeps having weeks like this one, don't count her out. Her wealth doubled from $10 billion to $20 billion, according to the website, thanks to a South Korean company buying a stake in one of her mines.

That figure still puts her a long way toward the likes of Carlos Slim ($63 billion), but it puts within striking distance of the top female on the list, Christy Walton ($24.5 billion). "This is simply an amazing story," writes James Thompson. "It is just six years since Rinehart became Australia's first female billionaire, but the resources boom and the quality of the assets inside Rinehart's company Hancock Prospecting means she is challenging for the title of the world's richest woman." (More Gina Rinehart stories.)