Steel Type of Daniel Brush's work

I have been reading about a fascinating goldsmith named Daniel Brush.

I would love to learn more about the type of steel he used for his amazing work.

Does anyone have a reference?

Wow very cool artist, thanks for sharing. Can you post some links to particular pieces you’re referring to?

Looking at a few pieces I think it’s mostly just patinated mild steel, with heavy engraving, inlay, chasing and repousse. I see a lot of Japanese influence in the techniques and style, but with more western non traditional imagery.

Maybe some parts are cast but it’s hard to tell.