Apparently the secret was a combination of the ore the wootz was made from and the blade making technique. Apparently the ore body played out some time before 1800 and the techniques were forgotten when the supply of that steel ran out.
From crystalresearch.com/crt/ab40/905_a.pdf
A number of papers and books have been published on the fascinating legends and excellent properties of
Damascene blades (see, for more recent examples, Refs. [1-5]). Genuine or wootz Damascus blades, known in
Russia as ‘bulat’, were manufactured in medieval Damascus from so-called ‘wootz’ steel which in turn was
made in India and characterised by a typical impurity content. Damascene swords, sabres and daggers became
famous for their hardness, retention of their cutting edge, mysterious secrets of the forging, quenching and
annealing procedures and a beautiful characteristic pattern of light-coloured wavy fine bands over the grey
background of steel. The museum-quality wootz Damascus blades were produced mainly in 16th –17th
centuries. In the early 19th century, the last secrets of the genuine Damascus steel got finally lost, but since that
time several attempts have been performed to rediscover the recipes of achieving blades of comparable quality
