please keep in mind that a lot of fakes are made of gold, to copy for numismatic value you want to get as much right as possible. Including alloy.
I have found many fake US gold coins...why, because they can bring %20 to x3 premiums...fakes of even common dates!
Some have a little bit of silver in the alloy...by XRF Test.
Keep in mind a fake Cob coin may only be a couple hundred dollars in any gold alloy...but can be several thousand sold to a collector or to a fooled suspect. Cobs are VERY easy to fake...Like I said. I have done it. Not to fool anyone, But for my own experimentation. For anyone with a half brain who has any jewelry or casting skills. its an easy task...anyone who takes the time to clean up the seam lines...can fool some experts.
2 months ago in Baltimore at the Biggest Coin show in the World I showed one of my fake 24k cobs...a 2 escudo. to a dealer. I asked him what he though, he was ready to plop down $800 to me...as i was wearing a dealer badge too. I said you better double check it. I know its a fake...How he said? Because I made it with my own two hands in 2003. he though the lack of crisp details was salt water damage...I said no, check the edge...casting. GOLD Does not get salt water damage. Had I removed the seam on the edge...an easy thing to do BTW. I could have taken this guy.
Moral is...BE CAREFUL when it comes to crude coins, especially cobs. Learn to look at crisp details, learn what mint luster is. Learn what original surfaces should look like. DO your research, and buy from only trusted Dealers who KNOW there stuff.
Also, its VERY important to inform people if its a fake...broken heart or not, not matter if they are a friend or not. If you dont, its as bad as telling a lie if you know better...otherwise, these same people will propagate incorrect information. This Will either.
1. Make them look bad or like a lair,
2. Get them in trouble if they ever go to sell it, or if someone in there family goes to sell it.
Moral is. Just because you care for someone...if you really care about them. For gods and your own consciences sake. Dont make them come across as a con artist, stupid, uninformed...should I go on? ignorance is not a favor.
Dont try to come across as a know it all either. get second opinions. There are plenty of professionals out there who will tell you straight up, hey, I think this is.
1. real,
2. Fake,
3. I am not sure, But I feel someone of better expertize should give you an opinion. Here is a reference.
And if they tell you its fake and offer to buy it, RUN. Be upfront that your just looking for authentication. A reputable Dealer will want you to be informed as its lends to better business down the road. They will tell you what it is. some history, and give you an estimate value.
All coins trade on pretty tight margins, Like an ounce of gold, Is it fair to buy at $20 under and sell for $20 over...of course.
All this information should be common sense.
No amount of Wishful thinking will make something authentic.
And if you know something to be wrong and dont disclose it, I feel that makes one just as bad as the forger and deceiver who made the thing in the first place.
Ignorance of course is forgivable.
But honesty is worth more than any gold. Even if it hurts. People do appreciate it! And, its the right thing to do.