King of Winter and Ice (asoiaf)

1. black iron: ravenry

2. grey iron: warcraft

3. yellow gold: economics

4. white gold: alchemy (chemistry)

5. copper: history

6. lead: diplomacy and law

7. grey steel: blacksmithing and metallurgy

8. black steel: architecture and engineering

9. silver: medicine and healing

10. brass: animal husbandry

11. bronze: astronomy

12. platinum: natural science

13. pewter: agriculture 

14. electrum: administration and logistics

15. zinc: language