Australia's richest person, billionaire Gina Rinehart, is being sued by one of her twin daughters over what reports said was a commercial dispute.
Hope Rinehart Walker launched legal action in the New South Wales Supreme Court. Her motivation remains a mystery although during a brief mention her barrister said it involved "the impact on commercial negotiations".
Gina, the only daughter of the late mining magnate Lang Hancock, inherited her father's business, Hancock Prospecting, 20 years ago and has turned it into a company now estimated to be worth Aus$10 billion (US$10.6 billion).
Gina, who shuns publicity and has seen her fortune double in the past year thanks to the commodities boom, famously fell out with her father when he married his Filipino maid Rose Porteous.
The two women battled for years over Hancock's fortune.
Gina Rinehart married twice, first to taxi driver Greg Hayward, with whom she had a son and daughter, and then to Frank Rinehart, a lawyer. They had twin daughters, including Hope, who has launched the lawsuit.