Vast mineral resources in Afghanistan have recently been discovered by American geologists.

Nigeria has oil, Angola has diamonds but neither has a stable political system or a booming economy spreading wealth to all its citizens.  GDP fell by 1.3% per capita on average in OPEC countries from the late sixties to the late nineties.  On the other hand, Norwegians are quite happily enjoying their oil revenue.

There are economic reasons for a resource curse.  The price of the resource can fluctuate on world markets and so can the income of the producer.  The income generated by the resource can push up the price of non-tradables and distort domestic allocation of inputs.  But I would guess all of these pale into insignificance with the political implications of a resource curse.

If the force of law is weak, there is an overwhelming temptation to steal resources.  Rents are dissipated by fighting or defensive expenditures. Leaders are short-termists and over-extract resources fearing they will be out of power soon.

The rule of law must precede development.  A windfall can provoke contests not prevent them.