I'm not chemist, but I know a bit about the elements. I have a rock book which tells about the different gems and rocks, under gold, it is you cannot scratch gold with your fingernail, but with a knife. I recently bought a 90% gold (10% alloyed with other harder metals) gold lucky angel. When it I got it it wasnt as good as condition in the picture, and it had a black mark on it, possibly a scratch that was filled in. I tried to rub it off with my fingernail, and got it into an argument to whether you can scratch 90% gold with your fingernail. I HIGHLY DOUBT this is possibly, granted, my rock book told me it wasn't possible, secondly, this isn't pure gold. It is alloyed with other metals, which makes it harder. Here's what he said: "And you wonder why people become frustrated with you ? I am well versed with the Periodic Table. I am also well versed with gold coins - both pure and alloyed. And they can both be scratched with a fingernail. For that matter, any coin - gold, silver, copper, nickel, aluminum etc etc etc can be scratched with your fingernail. Remember when I told you I would give you facts ? Those are facts !" What do you thikn of this?