As a coin buyer for gold I have bought coins from regular people looking to sell and not just from the coin stores. Fakes are always a concern in the back of my head when buying from non-dealer individuals. I have purchased this item called a fisch coin tester and used it every time I make a transaction.
They come available in various "wallets", with the "wallet" allowing you to test coins from that country. For instance, if I am buying American Gold Eagles Wallet #2 would allow me to test any of the sizes that they have in addition to the Krugerrands etc. Since the Gold Maple Leafs are different you would have to buy a separate wallet for that. The more "wallets" you buy the cheaper it gets.
The person that I have dealt with when purchasing these items was very friendly and answered any questions quickly. Here is the website below for those interested in checking it out.
fisch is way too expensive. A complete set is like $500. waste of money.
a simple digital vernier under $5 and a super accurate digital scale ( under $5 or $10) is all that is needed. Those prices include shipping.
go to ebay.
fisch is nice for the professional coin dealer only. coin dealers mostly skip over them. Prices will come down.
The "Fisch" detects fakes made out of "common" metals. Is Tungsten considered a common metal? I suspect "Fisch" does not classify Tungsten as common because it cannot distinguish between a gold clad tungsten "coin" and a real gold coin. Tungsten's density is nearly identical to gold's.
A quick story that might be useful...
A relative of mine owned some older silver rounds they had stored in their freezer. A few years later pulled them out to sell them. Upon opening the bag, they found that some of the rounds "surfaces" were flaking off... They decided to drill through one of the 'fakes' to find the metal appeared white in color. YUP, A silver plated round.
My guess is when the coins were frozen, the temperature coefficients of the different metals caused the silver plating to crack and separate away from the mystery metal. Might be another way to find out if your rounds are real.
Also watch out for fake morgans.. do your own due diligence!
This one $21 doohicky works great for 1oz (gold) Eagles, Krugerrands, Maples, Philharmonics, Buffalos, Pandas and Kangaroos. I was stoked to find it after I saw how much those Fisch ones cost (EACH!). This is much more reasonable and tests the same properties as the expensive Fisch. Mine arrived quickly and I recommend it.
As the price of silver rises I'm expecting more fake silver coins to surface, hopefully not in my freezer.