A smudge of blue paint decorating a letter in the Book of Kells may have come originally from the lapis lazuli mines in the heart of the Afghan mountains. The country's mineral wealth has been known about for a long time – bright blue scarabs and funeral ornaments made of Afghan lapis have been found in ancient Egyptian tombs – but its full exploitation has been prevented by chronic insecurity.
Just before the overthrow of the Taliban in 2001 I visited an ancient lapis mine in the side of the gorge in the Hindu Kush mountains in north-east Afghanistan. The road to the entrance of the mine was a rutted track which could only just be negotiated by our Russian-made jeep. We were far from the front line but even here war was having its effect. The mine was closed because all the miners had been called into the army of the anti-Taliban Northern Alliance which controlled the area. They had been ordered to swap their picks and shovels for Kalashnikovs and grenade launchers and join the group's assault on Kabul.
Deposits of lapis are small and easy to exploit and transport. In the Panjshir, the long arrow-shaped valley north of Kabul where there are deposits of the same semi-precious stone, local miners do not bother to dig but simply pack explosives into the hillside and detonate it. Some families make a living from this but bigger enterprises will have to battle with violence and corruption.
Geologists have long been fascinated by the potential for making Afghanistan an international mining centre. At the western end of the Himalayan mountain chain, the country's geological history is almost as dramatic as its historical past. As a result it has deposits of iron, copper, cobalt, gold and lithium. Some of them have been known for over a thousand years, but it is only recently that they have been studied in detail.
Yet the initial enthusiasm of mining experts usually wilts as they try to cope with the difficulties of establishing an industry in a country where so much territory is a no-man's land. Distances are long, infrastructure crumbling and communications poor.
Development is not impossible but the challenges are gigantic and everybody wants a cut of the profits. Just across the border in the Bajaur district of Pakistan, until recently controlled by the Pakistan Taliban, the Pakistan army found a note from a Taliban commander granting permission for a marble mine to reopen.
The risks and the rewards of exploiting Afghanistan's minerals are obvious, but the risks come immediately while the rewards only come in time.
The largest single foreign investment in Afghanistan is that of a Chinese company which is starting to mine for copper at Aynak, 20 miles east of Kabul. Over the next quarter-century it plans to produce 11 million tonnes of copper, build a power station and construct a road to Kabul. Even so, locals complain that the Chinese are not providing enough jobs for them and allege that bribes were paid to win the contract.
Some Afghans see their potential mineral resources as a reason why the US and other powers have intervened in the country, the Afghan equivalent of Iraqi oil. But sadly for the Afghans it will be a long time before they or anybody else benefits from their contorted geological past. Winning any sort of contract in Afghanistan involves bribery and anybody making money becomes a target for corrupt government officials and warlords.
One day Afghans will be able to exploit the riches beneath their mountains but the time is probably not yet.