By Richard Hamilton
BBC, Sakaraha, Madagascar
The unregulated free-for-all trade in sapphires is causing growing concern in Madagascar, with allegations of widespread corruption and an increasing use of child labour.
Madagascar's sapphires travel the world
The precious stone was discovered by chance five years ago, leading to a frantic scramble.
The country's sapphire belt, now thought to be the largest in the world, rakes in millions of dollars a year for gem dealers.
But there are concerns that the industry has little regulation and that the money ends up in unscrupulous hands.
The town of Sakaraha is Madagascar's biggest gem trading centre.
A few years ago there was nothing here at all - the town has literally sprung up out of nowhere.
It has been likened to the American Wild West towns where people come prospecting for gems in the hope of making a quick buck.
Mahatesa and Fernando work as Malagasy interpreters for gem dealers from Sri Lanka - they told me that in the precious stone trade, a lot of illegal business goes on.
"Some people keep the sapphires in their underwear so that it is easy for them to smuggle them out," they tell me.
However, one of the most disturbing aspects of Madagascar's sapphire industry has been the use of child labour in the mines.
Dominique Rakotomanga from the international programme for the elimination of child labour says the children work in extremely risky situations.
"The children are very small and it is them that can get into the small holes to see if there are precious stones to be found," says Mr Rakotomanga.
"If the walls of the mines cave in children can die or be asphyxiated in these holes".
Ever since sapphires were first discovered in 1998, the industry has been a largely unregulated free-for-all business conducted by dubious characters using shady tactics.
Now the government wants to formalise the sector and to ensure that Madagascar sees more of its profits.
"Stones here are never well cut and almost all of them are exported overseas which provides profit in other countries, which they would really like to have here," said Tom Cushman, a gem dealer from the United States.
Experts say that the amount of sapphire discovered so far is only the tip of the iceberg.
If that is true, Madagascar can expect to see more prospectors and traders - many of whom will become very rich.
But for Madagascar, one of the poorest nations on earth, managing that resource will be one of its biggest challenges.