Some people are aware of blood diamonds...
but this covers: timber, drugs, oil, mobile (cell) phones, laptops, pagers and other electronic devices containing tantalum capacitors.
If this is news to you (it was to me), you might want to have a read of this article.
There's also some nasty stuff going on with the US and UK in trades of torture instruments.
The Trade in Terror
U.S. firms export potential torture tools -Amnesty
PDF file - Amnesty International
Two companies are named in the PDF file, violating human rights.
Security and Defence Marketing Services and S&J Products are both mentioned.
S&J Products doesn't advertise their instruments of torture on their website however.