- The easiest is the ice cube test. (Test with a 5 franc silver coin and a nickel-plated Copper-Nickel coin, the melting speed of the ice cube is completely different). You can also push the edge of the coin through the ice.
From the pictures the corrosion on the surface does not look like silver corrosion (tarnish/oxidation/etc.). It looks like corrosion of the material underneath a (silver maybe) plating. That's why the test was inconclusive as it probably showed silver, iron, nickel or other elements not usually alloyed with silver.
Thema verschoben nach "Coin information and questions"(ZacUK, 2 Aug. 2024, 20:42)
The first rule for Chinese coins is assume it is a counterfeit until proven otherwise. Then provide weight in grams, diameter in mm, composition if known. and proper orientation of photos so they can be scrutinized for the community to better assist you. You cant find an exact match because it is similar to some genuine coins but it is a counterfeit. Genuine examples of this type coin can sell for millions of dollars, this is exactly why you can buy a variety of similar counterfeits by the bucket.