The sharpness of some ancient Obsidian Knives are unparalleled. U.S. surgeons sometimes use them because their blades are so thin that the healing tissues do not scar whatsoever, the material does not produce an allergic response, and the material does not leave behind residue (apparently some equivalently sharp metal blades leave microscopic 'files' that, in rare individuals, cause trouble).I took that tidbit of info in several years ago now; 2006 perhaps. It's possible that by now there is a superior metal knife on the market, but it is still pretty amazing that these ancient blades remained competitive into the new millenium.
When I lived in Central America I camped in the mountains for a while and one night, as my friend and I prepped our tent at an impromptu campsight, we found such a blade. At the time we didn't know anything about the history of such blades, and as I live in an area of the states where arrowheads routinely can be found in the soil, I mistook it for a weird arrowhead and let him keep it. I hope he still has it; it's a pretty cool souvenir, and quite possibly valuable, too.
