`Blood diamonds civil war`

Social externality. Tom notes that geological-region fingerprinting via impurity content makes provenance detectable for a "really good material scientist."

Augustine coined the term socio-engineering. This was printed in the National Academies magazine, and he talks about externalities. Externalities can be economic, they can be environmental, they can be political, they can be social. Anybody heard of blood diamonds coming from Angola? Civil war. The problem is, you can't always tell whether those diamonds came from Angola — but you can, if you're a really good material scientist. You look for the impurity content in the diamond. You analyze the impurities, and certain diamonds you can fingerprint to what geological region of the world they came from.