6 September 2010 Last updated at 01:15

California ownership battle over giant Bahia emerald

By David Willis BBC News, Washington
The Bahia emerald - named after the region of Brazil in which it was discovered - weighs 380kg (840lb).
It is said to be worth more than $370m (£235m) - and at least six people are claiming they are the rightful owners.
A judge will hear from all the parties claiming ownership of the gem before deciding the case in October.
One those at the centre of this dispute is Anthony Thomas, a construction executive from California, who says he paid two Brazilian gem dealers $60,000 for the emerald shortly after it was unearthed nine years ago - a fraction of its current value.
Mr Thomas says he arranged to have the stone shipped to his home in San Jose, but that it never showed up.
He believes he was tricked into believing it had been stolen so it could be resold for more money.
Mr Thomas is just one of those claiming ownership of the giant emerald.
One problem he faces is that - as he awaited its delivery - a fire broke out in his house, destroying his receipt.
The emerald did eventually make it to America, although whose possession it has been in since then is a matter of some doubt.
One thing that is known is that it spent some time in a bank vault in New Orleans which was flooded during Hurricane Katrina, leaving the valuable gemstone underwater for several months.
It was subsequently taken to Las Vegas for inspection by a potential buyer, where it was seized by the Los Angeles sheriff's department.