Hi, I was playing with some Damascus and etching solution one night a while back and came up with an etch I liked. So after cleaning off the acid I coated the blade with 4 and 1 oil to help set the etch. Then for some reason I don't remember put the blade in a toaster oven at 350 Degrees for a while. When I pulled it out the bright silver and black had turned to gunmetal blue and dark brown. I liked the effect so I kept it. Turns out it is pretty durable too.