...They're simply indistinguishable from the real ones. The gold is cold, heavy and has a natural patina.
Unless the fake is made from real gold then it will be very much distinguishable from the real one. Given the price I doubt it is made from real gold so it will not be nearly as heavy as the real one. Perhaps from looking alone you could not tell, but if someone picked it up they would know right away.
Your title is misleading. I came here because the title indicated a gold coin only to read that it was a replica.
This since its so small (the size of a penny) is dense, and feels a lot more real than a bigger gold coin replica.
I think the realism with this coin is incredible. It even has a patina on it that a natural gold coin would. I think its definitely worth 1 BTC to somebody.
About the title-I apologize, its revised.
