1. Damascus Steel
An impressively strong type of steel, this metal was used across the middle East between 1100ad and 1700ad but disappeared around 1750ad. Used predominantly for weaponry, no one is quite sure why it fell out of use but many speculate it is because the ores needed to create it became scarce. There are recreations of the material available but they are not quite the same or entirely successful in their reproduction of its strong qualities.