I was wondering about that myself. I assumed it wasn't rust as you could only see it at certain angles just like the other patina, and it does have any noticeable texture. I figure even light rust will have a noticeable change in texture on the finish. Also checked today and it started to fade into more subdued grayish red, but I didn't wanna say anything since I'm not 100% certain and this is the first knife with that color patina. It's only on the cladding too which is weird. The core is a rainbow blue.