I've got a large piece of very special metal from the WTC towers in NYC. It's a roller bearing from one of the elevator shafts of the tower that a close friend and first responder gave me as a gift. I want to bring it back to life in another form (a knife or two) and need to confirm metallurgy. Does anyone know the easiest way to do so? I believe in talking to sources from a previous job in the metals industry that it is 52100, but there is a chance it could be a semi-stainless steel of some sort. It definitely has patina on it, but doesn't seem as reactive as 52100. Any suggestion for how I could confirm the steel that doesn't cost a fortune or require international mailing? I've used a x-ray gun on it but it comes back as a high carbon steel without specifics.