Hello there Alex,
very nice collection you've got there
That sword certainly is a trade blade in arab mounts. The blade also is very beautiful, its quite rare to find a damascus blade in arab mounts. Though the mounts do not seem old.
As to the dirt, in my trip to Riyadh, when I was talking to that old man, Al-Suffayyan, I asked him about how to restore a wootz pattern, I mentioned the common method of acid etching, and he looked at me in a funny way. He told me he, and locals used to use a special kind of dirt, the name escapes me at the moment, which is brought from 'a far away land'. Once it touches the blade, the 'veins' as he called them, bloom out. I guess you somehow got hold of this same dirt.