Even back before China was counterfeiting every coin that worth anything.the Greeks & Roman and others were making there own counterfeits just to live or undermine an empire? so how do you tell if it is a new or old counterfeit?
Well first of all, I doubt you're going to find many modern fourrées. Fourrées were a type of counterfeit that had a base metal core wrapped with silver or gold. There really isn't much of a point in doing that today (as the metal in the coin will be worth less than what it sells for, and if you're not going to make it all silver/gold, you might as well use a metal that looks precious but isn't all the way through, anyway), and I have never heard of a modern counterfeit of one of these. Ancient counterfeiters would never make a counterfeit in precious metal*, since the entire point was to use less precious metal than the legitimate currency, while it makes perfect sense for a modern counterfeiter to use such metals. Also, aside from Limes denarii, which are generally easy to spot, ancient precious metal coins were never cast,** so if you see an ancient coin that looks cast, it's probably a modern counterfeit. In addition, many ancient counterfeits are in crude style and have numerous spelling errors that wouldn't make any sense for a modern counterfeiter to copy. For instance, I have a fourrée of Trajan that misspells the emperors name on the front, and the inscription trails off into gibberish on the back. Modern counterfeiters wouldn't make mistakes that obvious, but illiterate ancients trying to recreate coins from memory or a worn coin would. There's also the factor that many modern fakes are done in a style that's obviously wrong, but also obviously not ancient. That's something you really just need to develop an eye for. There are also databases of fakes you can look through to check coins against known fakes. *There were some coins in India that crudely immitated Roman denarii, probably to ensure that people would think that it had the right amount of silver in it (which they actually did), but they look very crude and obviously not Roman. There are probably a few others, but in general, if it's entirely made out of a precious metal, it's not an ancient counterfeit. **I recall reading that in some places like Gaul, they would in fact make cast fakes of sestertii. I don't know enough about them to tell you that much about how to tell them from modern casts, aside from the fact that if it's really, really crudely done, there's a decent chance that it's ancient, since modern forgers usually aren't that bad at it.
Gao's answer was very good! The point to remember is that ancient counterfeits were made profit by containing less metal than appropriate. Ancient copies with full value metal were made to circulate where coinage was in short supply. India certainly did this but they were not alone. In many cases, these copies are as valuable today as the coins they copied since they really were the circulating coin of some region. Most are easily identifiable by their style. Beginning collectors need to beware of modern copies. The best answer is to buy from dealers who you trust, who specialize in ancients and who guarantee 'for life' purchases to be genuine. In time, you develop a feel for what looks right and what does not and you will start buying from people that know less about the coin than you do. We all make an occasional error. We all need to avoid buying things 'too good to be true'. After seeing some of the Chinese copies of modern coins, I do not believe the 'problem' in ancients is anything like as bad as the one in moderns but that mostly means that I have no experience handling 1793-4 US but have examined well over a thousand Roman coins from 193-4 AD. I could be fooled with either but I'll risk it with a 193 Roman and would not touch a US 1793 coin without papers.
Three words: Experience. Experience. Experience. Just one more reason to buy the book before the coin. I'm a pretty quick learner, so I got pretty comfortable at spotting fakes in my limited area of specialization after handling only several hundred coins, including just a few dozen fakes.
