A STORTA for comments

[A Senefelder]

however water finds sudenly exposed to oxygen may have a surface orange oxidation arise.

Sure does. I get my wrought iron from a length of river that once had 20 19th century mills along 1/8 of mile that were destroyed in a dam burst 100 years ago. Every piece I've ever fished out of the water will very quickly do exactly this until I clean it for use in forging. They all have the same surface appearance of the OP's sword once they come out of the river and dry.