Fake Double Bison
Fake goldThere have been rumors about fake double bison coins, maybe gold plated. Rumor is a 5 oz fake coin, that weighs 3 oz, was created by Tri-State mint.
Tri-State did mint some gold plated brass medallions for the South Dakota Centennial in 1989. Also, they did tend to play around a little as there are some German Nazi coins they did that were dated 1989 and looked like the real thing.
Here are some details on fake gold.
You can weigh gold to see if the weight matches up with the weight listed on the coin. Remember, it is measured in Troy ounces, which is 14 oz to the pound. But for bars, tungsten is used to fill fake gold bars.
Gold is Assayed to determine its gold content. There are several ways of assaying gold, you can assay with X-RAY florencesence scans, or by scraping some gold from the surface. Since tungsten is approximately the same weight, for gold bars, they usually use a core boring method to determine if it is a tungsten bar with a gold plating.