Why is Americum more expensive than Uranium?

[CognitiveNet]

The cost of Americum:

Cost, pure: $1500 per g (1,5 million USD per Kg)
Cost, bulk: per 100g

The cost of Uranium:

US $ 51,5/lb (at 25.07.2011) or 11,3 cents per gram (natural uranium in the form of the unrefined oxide U3O8).

Why is Uranium so much cheaper?

 

[DrDu]

If you look for Americium (and not Americum) you may find some information in wikipedia.
In contrast to uranium, Americium does not occur in nature which explains it's high price.

 

[jtbell]

You can dig uranium ore out of the ground. You have to extract americium from spent fuel for nuclear reactors. According to the Wikipedia article, one ton of spent fuel yields about 100g of americium. That's a ratio of about 0.0001 or 0.01%. And spent reactor fuel is a lot more radioactive than uranium ore, hence requires more care (and cost!) in handling.