The most famous steel in history is one nobody can reliably reproduce. Damascus steel refers to two entirely different things, and conflating them causes real confusion. The original, called wootz, was a crucible steel produced in southern India and Sri Lanka from around 300 BC, traded west as cakes of raw metal and forged into blades across the Islamic world. The modern version sold today is pattern-welded steel. It looks similar and is made by a completely different process. True wootz began with iron, carbon-bearing plant matter and a sealed clay crucible held at heat for hours. The result was hypereutectoid steel at roughly 1.5 per cent carbon, far beyond the 0.8 per cent where cementite begins precipitating out of solution. That excess carbon is normally a defect. Cooled badly it forms brittle networks along grain boundaries. Cooled and cycled correctly it does something else. - Slow solidification nucleates cementite on trace carbide-forming elements in the ore, chiefly vanadi...