Bought for $60,000, but worth $400m – the battle for the world's biggest emerald

The curious case of an enormous emerald weighing about as much as a horse was set to be finally heard in a Los Angeles courtroom yesterday, when a judge began his efforts to try to determine precisely who owns it.

Dug up in Brazil in 2001 and tipping the scales at 840 pounds (381 kilograms), the boulder-sized Bahia Emerald is one of the largest gems ever discovered. Several people have laid claim to it. Yesterday, a small army of lawyers was set to cram into a tiny courtroom hear Superior Court Judge John A Kronstadt review the case of the man who says he bought it first.

Tony Thomas has said he purchased the emerald from a Brazilian gem dealer for $60,000 (£37,900) shortly after it was excavated. Its worth has since been appraised at almost $400 million. Mr Thomas says that after he arranged to have it shipped home, he was tricked into believing it was stolen so that it could be resold for more money.

He says it vanished after he turned it over to people who were supposed to ship it to him and, now that it's been found, it should be returned to him.

The case will be weighed from the bench by Judge Kronstadt without a jury. Lawyers for other interested parties have argued that the claim should be dismissed because the emerald was never delivered to Mr Thomas, but his lawyer says he did acquire the emerald before it disappeared. The judge will review other claims later.

After it vanished, the rock's journey became muddled. It once wound up in a New Orleans warehouse which was flooded during Hurricane Katrina.

One claimant says he was retained by the Brazilian owners to sell it. Another says he got it from a gem dealer as collateral for a shipment of diamonds he paid for but never received. He was trying to sell the gem in Las Vegas when authorities seized it.

The Los Angeles County Sheriff's Department now has the emerald under lock and key.