Nanotech Used 2000 Years Ago to Make History's Sharpest Swords

Damascus swords -- sharp enough to slice a falling piece of silk in half, strong enough to split stones without dulling -- owe their legendary qualities to carbon nanotubes, says chemist and Nobel laureate Robert Curl.

The blades used so-called wootz steel, smelted with a technique developed 2000 years ago in India, where craftsmen added wood and other organic debris to their furnaces. The resulting carbon-laced steel, hard but flexible, was soon celebrated across the ancient world.

Perhaps because the tungsten-rich ores used to make wootz steel ran out, the making of Damascus blades stopped during the 18th century. The techniques vanished from metalsmith lore. Modern metallurgists tried again and again to recreate the blades, but without success. Then, a little more than a year ago, German scientists explained their difficulty: wootz steel was full of carbon nanotubes, a miracle material "discovered" in 1991.