If A Bunch Of Examples Of A Super Rare Coin Suddenly Come Onto The Market, Does That Indicate Fakes?

About 40 years ago a French coin magazine had an article about the 1868-BB (Strasbourg Mint) gold 100-franc coin. It appeared that several examples in Uncirculated condition had been listed by dealers around the same time. It's considered the key date of the series. The author of the article speculated that a pair of dies may have been smuggled out of Strasbourg Mint during the confusion that followed the end of the Franco-Prussian War, and that the dies may have ended up in the Far East. I have never heard any more about this in all the years since.

Excellent point! This has happened so many times and the coins were legit and valuable! If a large hoard or collection is dispersed, generally the Numismatic community will be informed. There are many old time collections that go to auction quite often.

We just have to know our coins and research them for proper identification, and keep our eyes and ears open.

If we are talking ancient and medaieval coins, then there are "surges" where once-rare coins suddenly become plentiful. This is usually as a result of modern geopolitical changes. For example, ancient Roman coins from the Siscia mint were once fairly difficult to find. Suddenly, in the 1990s, the market was flooded with them. Why? Coins from Siscia circulated mostly in the territory surrounding Siscia, which for most ofthe 20th century was Yugoslavia, a formerly closed communist country where metal detecting was forbidden. Then the iron curtain fell and furthermore Yugoslavia disintegrated into civil war. Wars and turmoil usually cause antiquities to flood the market. Siscia is now one of the most common mints for late Roman bronzes.

Likewise, Afghanistan-sourced coins (Bactria, Indo-Greek, early Afghan Islamic dynasties, etc) became much more common during the Western occupation of that country.

Nevertheless, there are also surges caused by counterfeiters. The "Black Sea Hoard" coins were the most notorious example in recent years: in 1988, a fellow in Bulgaria got mad at a German coin dealer for lowballing him and buying ancient Bulgarian coins too cheaply, so arranged to have thousands of fake ancient coins made and funneled through that German dealer. It took over a decade for them to finally be proven fake.

Modern coins are not immune from fake surges. In the 1970s in Australia, there was a sudden surge in Russian Empire 15 rouble gold coins turning up at Sydney coin dealers. Turns out most of them were freshly-minted debased-gold Eastern European fakes. Crewmen from Eastern European cargo ships would come ashore and sell the dealers rolls of these gold coins; the two coins on the ends of the rolls were genuine (and it was these end-of-roll coins that saw the most scrutiny from the dealers), but the bulk of the roll were fakes.

Very informative, Sap!

Historically, hoards have come available, to drastically change the market. When the " Morgan dollar Hoards" held by the Federal Government, were released to the public, $1000 bags were sold for face value and certain dates/mints that were once deemed semi-key and somewhat rare, flooded the market ... changed it forever. I'm new enough to know that I personally must research coin data, in order to protect myself ... I've been burned.

@tdziemia The sources that I use to look up how many examples of a particular coin have sold and for what amount in the past are mostly from the bigger American auction house archives (the usual like Stack's, Heritage, GC, and others), as well as some of the archive websites any person can subscribe too for more international information (European for the most part). However, many of these services don't include data and information from auction house records in Asia (language barrier probably). Plus, there are many domestic and international auction house archives that can't be easily found online unless you know that the auction house exists. So, perhaps the data I have as an amateur is skewed and doesn't paint the full picture. I'd imagine though that if the vanguards of numismatics here in the US don't often see a particular type of coin, than smaller auction houses will rarely if ever see that coin as well. Of course, maybe in the US some coins are rarely seen because all the collectors are abroad in Europe or Asia, where those same coins may come up for sale a lot more often and the news just never travels here because the interest is more niche to us Americans.

@Secret Argent Man Would you care to elaborate more on your idea? It sounds interesting!
When I mention a super rare coin, I don't necessarily mean a coin that is worth thousands of dollars, or even tens of thousands of dollars. From what I've seen, there are many many coins that only come up a handful of times each year or every other year, but they don't cost an arm and a leg. They're just not popular. I'm talking about a coin that might have sold for maybe $800-$1500 six years ago, but then suddenly, a bunch comes up for sale and they all sell for between $150-$400, or even less. The same goes for tokens as well.

If I was a coin enthusiast working and living in a place where $150 is a lot of money (a couple weeks to a month's salary), of course I'd consider trying to manufacture modern forgeries, especially if I have experience in craftsmanship, jewelry, or metal working. I could potentially turn $1 worth of raw materials into 100x or even 1000x that. There's an incentive for someone out there to do this, and I'm curious to know of more examples in this hobby's history where many "experts" at the time were fooled by the really good counterfeiters.

@newguy, thanks for the answer.

I collect some places that are relatively obscure to U.S. collectors, and that come up far more often in European auction houses that are regionally focused, than places like Heritage and Stacks. While you haven't come out and said what coin types you are referring to, I can imagine your situation could be something like mine.

Hence my question/comment about the notion of rarity, and how one comes to that conclusion.

The rarest coins in my collection have not come up for sale in at least 20 years at any U.S. auction house. But they do come up occasionally at auction houses that are are represented in acsearch and the Sixbid archives. So I understand a number of the points you've made (and continue to be curious about the specific coins to which you are referring).