Thank you for the information. It’s definitely carbon. All blades have what appears to be some natural patina, but there’s been some rust as well. I’m pretty dang fond of this knife. I wonder why Queen was never very big down here (MS) in the Deep South. Growing up of course I knew Case and Schrade and Buck and the like, but I was seriously an adult before I ever heard of Queen knives. I’m sure I’ve owned knives made by Queen with stamps from other companies, but I didn’t know it at the time.