I agree with brownshoe, D2 seems to resist a patina, but pit more readily than straight carbon steel. I neglected to oil a queen folding hunter after carrying it in a sweaty pocket for a day. 2 weeks later when I opened it up there were tiny little black specks peppering the blade. A little metal polish and elbow grease took care of it, but it was surprising. I have used that folding hunter for a lot of apples, and meat cutting and had next to no patina form. Joe