You could also take a look at the damascus material on the KeyShot Cloud. Maybe the colors could be altered to make a timascus material.
P.S.
I'm not sure how familiar you are with timascus, so please forgive me if you already know this. Since timascus is a heat anodized titanium, using the metal material and picking measured Titanium with the anodized option may help you get the colors right.