I am hoping some of you might help offer some advice on what I believe to be a meteorite. My elderly and not well brother-in-law bought this at the Tuscon Meteorite, Mineral and Gem show from a seller from Latin America back in 2000. He says he has paperwork somewhere, but I am not holding out a lot of hope he can find it. The seller told him that the "meteorite" came Patagonia. It weighs 74 pounds and measures 16"x12" and varies from 3-1/2" to 4-1/2". From the photos I have looked at online, I think it most resemble an iron meteorite. I have attached some photos. One blowup shows a 1/8" diameter hole and a second shows a dime-size area that is shiny silver almost like it was polished.
So, my questions is what is my next step? I have read online that a small 1-2 gram slice should be sent to a lab for analysis and authentication. I hesitate to do that and not do it correctly and possibly compromise the value. Thanks in advance!