Over the following eight years, it is estimated Unita sold $3 billion worth of diamonds, largely to arms dealers from the former Soviet Union state of Ukraine. The dealers would fly in with plane-loads of Kalashnikovs, tanks and rockets; Savimbi would swap them for bags of precious gems. Within a few years, he had transformed a raggle-taggle bush army into one of the best-equipped irregular forces in the world.
The savagery of the ensuing war devastated Angola. Entire towns and cities were flattened and millions of land mines were planted. More than half a million Angolans are estimated to have died. Tens of thousands more have been maimed.
Further up the west coast of Africa in Sierra Leone, Foday Sankoh and his Revolutionary United Front rebels have also fought viciously with gem money, clearing thousand of civilians from diamond-rich territory. Their tactic was to instill fear by randomly hacking off arms and legs. Sankoh's forces also humiliated the UN by holding 500 peacekeepers for several weeks last May, although Sankoh was arrested the following month.
And in the Democratic Republic of Congo, war broke out two years ago, involving six outside countries and at least nine different armies. Some are battling to oust President Laurent Kabila; others want to prop him up. Diamonds are not the cause of the war - but they have proved a very lucrative war booty.
On the rebel side, Rwanda has openly admitted it uses the diamond wealth to subsidise its actions against Kabila. Individual Ugandans have also profited - perhaps as much as the state. "There is no doubt the government feels deeply uncomfortable about the fact some officers have clearly made vast amounts of money," says Aidan Hartley, political analyst with the International Crisis Group.
On the government side, the President has doggedly defended key towns in the diamond-rich south-east of the country. He was rescued from almost certain defeat at the outset of the war by the Zimbabwean army - which was subsequently rewarded by lucrative diamond concessions.
But the Congo conflict is very different in nature from Sierra Leone or Angola. Whether diamond exploitation is fuelling the fighting, or is merely a convenient by-product, is debatable.
Global Witness, the UK lobby group spearheading the "blood diamonds" campaign, believes all Congo diamonds should be boycotted until the war is over. The deprivation of the poverty-stricken local populations would be an "unfortunate consequence" of the ban, concedes Alex Yearsley of Global Witness. And while diamonds are the most obvious resource for rebels to trade - and for well-meaning western groups to identify with - Congo is blessed with fabulous natural resources such as hardwoods, coffee and other valuable minerals that could be exploited almost as easily.
"It's a touchy-feely issue rather than one that goes to the heart of the conflict," says Hartley of ICG. "Its value is possibly in reaching people who might not otherwise have noticed another nasty war on a forgotten continent. And I think that's a good thing."
At any rate, a complete ban on "conflict diamonds" is considered unworkable by those who know the trade best.
IN an air-conditioned room above a deserted restaurant, the man with a monopoly over the Kisangani diamond trade sits eating spicy bread and sipping coffee from his native Lebanon. Hacking rough chunks from a tin marked Kraft cheddar cheese, he curses his new home and the life of a diamond kingpin. "I don't mind if it's expensive here, but when this is all you can get! You can't imagine how we live. It's certainly not Las Vegas or the Champs-Elysees," he grumbles.
Musa Hassan is one of the thousands of middlemen who link rough diamonds from rough places with the sanitised markets of Europe and the US. He buys from middlemen, who buy from the jungle mines. Then he boards a plane for the Rwandan capital Kigali, changes for Brussels and finally arrives at the northern Belgian city of Antwerp, where 80 per cent of the world's rough diamonds are traded. There he disposes of the small bags at a very large profit.
A veteran of Angola and Sierra Leone, he was working on the other side of the front line, in the Congolese capital Kinshasa, before President Kabila got too greedy. In August, he came to Kisangani, where the Congolese Rally for Democracy (RCD) offered him a monopoly on the business. They get their cut, too - reportedly $100,000 a month.
But business is not good, Hassan moans. The Ugandans and the Rwandans control the richest mining areas. Now, instead of passing through Kisangani, the stones are exported directly through other dealers who have set up shop in the five-star hotels of Kigali or the Ugandan capital, Kampala.
Any ban on Congolese diamonds cannot work, he says - it's too easy to pass the stones off through other countries with weak governments and pliable officials. Already, many Congolese diamonds are being sold with paperwork from Bangui, the capital of the neighbouring Central African Republic.
That problem has, indeed, surfaced in previous attempts at regulation. Sierra Leone's rebels circumvented a diamond ban by shipping them through friends in neighbouring Liberia. In a couple of years, Liberian exports jumped from negligible levels to $200 million. Now Liberia is subject to a UN embargo.
De Beers, meanwhile, is trying to clean up its stained image, with a claim this year that none of its diamonds come from conflict zones. The announcement was met with scepticism, given the nature of the industry and the notoriously lax ethics of dealers at the four Antwerp diamond bourses. But campaigners have acknowledged that the industry is finally cleaning up its act. "We're telling people they have a great amount of power. They can ask their retailer what he has done to find out if the diamonds they sell come from a Unita or RUF area," says Yearsley of Global Witness.
Consumers, meanwhile, are showing little sign of losing their appetite for sparkling stones. Diamonds are not the new fur. Sales of diamond jewellery grew by 12 per cent, to a colossal $25 billion in the US, the world's biggest market, last year.
Hassan, who has been working in the trade for 35 years, is convinced diamonds are forever. "I don't think if you take a diamond to your girlfriend or your mother they will refuse it," he says. "They will say thank you and give you many, many kisses."
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Websites: International Crisis Group: www.intl-crisis-group.org Global Witness: www.oneworld.org/globalwitness