It’s possible you have heard of Damascus steel, particularly if you are familiar with old swords, knives and guns. A book, The Art and Beauty of Damascus Steel, has been written on the subject. While this treatment of the topic might not do the book justice, Damascus steel is quite beautiful and holds much mystery.
Although the heyday of Damascus steel was between 900 and 1600 AD, the origins began as early as 300 BC in India. At that time, wootz steel was made using a new technique that produced high-carbon steel of unusually high purity. Glass was added to a mixture of iron and charcoal in a small, sealed, clay crucible, and it was then heated. The glass acted as a flux to combine with other impurities in the melt, allowing them to float to the surface. The result was a more pure steel. This technique spread from India to modern-day Turkmenistan and Uzbekistan around 900 and to the Middle East around 1000.